THE SPIDERS AND ALLIED ORDERS OF THE BRITISH ISLES

COMPRISING DESCRIPTIONS OF EVERY FAMILY OF BRITISH SPIDERS, EVERY SPECIES OF HARVESTMAN AND FALSE SCORPION ALSO THE MORE FAMILIAR OF THE BRITISH MITES AND SEA-SPIDERS BY THEODORE H. SAVORY, M.A., F.Z.S. AUTHOR OF "THE BIOLOGY OF SPIDERS," " THE ARACHNIDA," ETC.

WITH 63 FIGURES IN COLOUR BY FLORENCE M. BRUMMITT

ALSO 130 ILLUSTRATIONS FROM DRAWINGS AND PHOTOGRAPHS AND 88 DIAGRAMS IN THE TEXT

Biblioth~que Centrale Mus6um

111111111111111111111111111111111111111 33001003953858 FREDERICK WARNE & CO. LTD. Frontispiece. P!. I. LONDON & NEvV YORK THE GARDEN SPIDER A ranea diadem a ~ (X z) p. 130. PREFACE TO THE SECOND EDITION purely academic question as to whether they may properly be regarded as Arachnida or not, few of my readers are likely to be concerned ; but the most recent opinions CONTENTS consider them to be much more closely allied to the PAGE Arachnida than to any other class of Arthropods, so that INTRODUCTION TO THE ARACHNIDA - • • • 17 The Orders of Arachnida ; General Organization · I have taken this as sufficient justification for giving some Collection; Preservation ; Methods of Study- ~ description of an exceptionally interesting group of animals, STRUCTURE AND HABITS - feeling that the opportunity to do so was too good to be CLASSIFICATION OF SPIDERS neglected. BRITISH SPIDERS-ORDER ARANEAE - THEODORE H. SAVORY. FAMILY: MALVERN COLLEGE, Atypidae - 45 1944· Segestriidae 47 Dysderidae 48 Oonopidae 49 Hahniidae­ 51 Argyronetidae 52 Anyphaenidae - 54 Sparassidae 54 Ctenidae - 55 Thomisidae 56 Drassidae - 63 Clubionidae 66 Salticidae - 72 Sicariidae - 77 Pholcidae - 78 Mimetidae 79 Uloboridae 81 Dictynidae 81 Eresidae - 83 Ciniflonidae 83 Agelenidae 84 Pisauridae· 90 Lycosidae­ 91 Oxyopidae 96 Theridiidae 96 Linyphiidae 104 Argyopidae 122 IO II

11 CONTENTS PAGE 135 BooKs ON SPIDERS - . LIST OF PLATES BRITISH HARVESTMEN-0RDER 0PILIONES - 136 Structure and Habits 136 152 Note.-All figures shown in the Colour Plates are females except Classification one figure on Plate 16. FAMILY: FACING Trogulidae 153 PLATE PAGE N emastomatidae I 56 I. The garden spider Aranea diadema - Frontispiece 159 Phalangiidae 2. Portion of a leg of Ciniflo, showing calamistrum IS 174 BRITISH FALSE-SCORPIONS-ORDER CHELONETHI 3. Leg of a spider I9 Structure and Habits 174 . Portion of a spider's leg showing spines 22 1So 4 Classification 5. A spider's foot showing toothed claws 23 FAMILY: 6. Foot of a garden spider showing the third median Chthoniidae !SI claw - 26 Obisiidae - IS2 7, Mouth parts of a female spider showing poison fangs ldeoroncidae 1S3 and palpi - 27 Cheiridiidae IS3 s. Mouth parts of a male spider showing poison fangs Chernetidae 1S4 and palpi - 30 Cheliferidae rss g. Spinnerets of a garden spider ---- 3I BRITISH MITEs-ORDER AcARI - rSS 1o. A spinneret showing tubes through which the silk SUB-ORDER: issues 32 Parasitiformes - 1SS u. Atypus ajjinis, Harpactea hombergi, Segestria senocu- Trombidiformes - 190 lata, Dysdera erythrina 33 Sarcoptiformes - I92 12. Portion of the skin of a garden spider 34 Tetrapodili 193 13. One of the spiracles of a garden spider 35 BRITISH SEA-SPIDERS-SUB-CLASS PYCNOGONIDA 195 14. (a) The water spider Argyroneta; (b) Diving Bell of Argyroneta . 36 Structure and Habits I95 .IgS 15. Palpi of Harpactea hombergi and Antistea elegans 37 Classification 16. Argyroneta aquatica, Anyphaena accentuata, Zora FAMILY: spiniinana, M icrommata viridissima 40 Nymphonidae 200 201 [ 17. Micrommata viridissima. A hunting spider 41 Pallenidae - rS. Palp of Hahnia montana. Palp and Epigyne of Phoxichilidiidae - 201 202 Micrommata viridissima 44 Chilophoxidae 19. Salticus scenicus. The Zebra spider with captured Ammotheidae 203 Tanystylidae 203 ~ ~ 203 20. Epigynes of Zora, Clubiona brevipes, Scotophaeus Pycnogonidae blackwalli and Palp of Clubiona corticalis 46 APPENDIX oN NoMENCLATURE - 205 21. Female of Cinifto with young 47 GLOSSARY 215 22. Xysticus viaticus, Misumena calycina, Tibellus parallelus, Diaea dorsata 4S INDEX 217 12 13 LIST OF PLATES LIST OF PLATES .FACING FACING PLATE PAGE PLATE PAGE 7. Th~ridion pallens with its characteristic cocoon _ 4 91 23. Epigyne of Clubiona holosericea and Palp of Clubiona 4S. Ep1gyne~ of Tarentula carinata and Trochosa terrestris · 49 terncola - - - _ _ 94 24. A web spun by Agelena in two months 50 49· Theridion with young _ : : 95 25. Drassodes lapidosus, Scotophaeus blackwalli, Clubi- 50. Theri~ion redimitum, Theridion notatum, Theridion ona subtilis, Agroeca brunnea 51 bzmaculatum - - _ _ _ _ 96 z6. Epigynes of Clubiona terrestris and Salticus scenicus 54 51. Palpi <;>f . Stearodea bipunctata and Theridion 27. (a) Agelena labyrinthica; (b) Tegenaria atrica, a redzmztum - - _ _ _ _ 97 house spider 55 52. The h~mm~ck-web of the sheet-weaving spider 28. Epigyne of Evarcha blancardi and Palp of Uloborus 58 Lznyphza - - - _ _ _ _ 9S zg. A hunting spider, Pisaura listeri, with cocoon - 59 53· Asagena phalerata, Episinus truncatus Stearodea 30. Salticus scenicus, Evarcha blancardi, Euophrys bipunctata, Theridion denticulatum' frontalis, Ero thoracica 62 54· Epigyne and Palp of Theridion varians 1 ~~ 31. Palp of Cinifto similis and Epigyne of Cinifto 55· Sheet webs of Linyphia amongst gorse _ _ 103 jenestralis - 63 56. Epigynes of Theridio?t pallens, Maso sundevalli and 32. Pisaura listeri at work on its silk tent 66 Leptyphantes mznutus - - - _ 105 33· Pholcus phalangioides, Ciniflo similis, Agelena laby- 57· Sheet web of Linyphia with its characteristic super= rinthica, Amaurobius atropos 67 structure - - - _ _ _ 107 34· Epigynes of Agelena labyrinthica and Amaurobius 5S. Stemonyphantes lineata, Labulla thoracica, Lepty= atropos 70 phantes nebulosus, Hypomma bituberculata IIO 35· Pisaura listeri. The female resting outside its silk 59· Palp of Bathyphantes dorsalis • _ _ 1 tent - 71 6o. A fine specimen of an orb web. The work of II 36. Epigynes of Cinifto jerox and Textrix denticulata - 74 Aranea - - - _ _ _ 4 37· Tent of Pisaura listeri with egg cocoon inside • 75 61. Walckenaera acuminata Savignia .r;rontata G - II o b . ' . )' ' ona- 38. Tegenaria domestica, Tegenaria silvestris, Pisaura tzum ru ens, Lznyphza montana -- listeri, Dolomedes .fimbriatus- 78 62. Palp of Bathyphantes nigrinus _ • • • II5 39· Epigynes ofTegenaria.domestica and Tegenaria atrica 79 63. Webs covered with hoar-frost _ _ nS9 40. Pisaura listeri. The female has torn away the 64. Epigynes of f..:eptyphantes nebulosus, L. lepros~s and II tent to enable her young to leave it -- So L. alacrzs - - . _ _ 122 41. Lycosa saccata, Arctosa perita, Trochosa terricola, . 65. An almost invisible web of a garden -spide~ • 123 Pirata piratica ------Sr 66. Tetragnatha extensa, Tetragnatha montana, Pachy- 42. Palp of Tegenaria atrica and Epigyne of Tegenaria . gnatha degeeri, P. clercki - - _ _ rz6 parietina Sz 67. Ep1gynes of Leptyphantes pallidus, L. pinicola, 43· (a) A Wolf spider Lycosa with cocoon; (b) Lycosa ·. L. . obscurus and L. ftavipes _ _ _ _ with young covering her body . --- 83 6S. The. sp1d~r M eta reticulata resting in its web _ _ ~~~ 44· Epigynes of Tegenaria silvestris and Pisaura listeri S6 6g. Zygzella httera_ta, Aranea cucurbitina, Cyclosa conica 45· Pirata piratica, the water Wolf spider capturing M eta retzculata· - - - - ' 129 a water-skimmer S7 7°· Palp of m~le Leptyphantes ~ristatus and Epig;nes of 46. Epigynes of Lycosa pullata, L. saccata, L. nigriceps L. crzstatus and L. zzmmermanni 130 and L. tarsalis -- • • -- go I5 14 LIST OF PLATES

FACING I PLATE PAGE I 71. The spider M eta reticulata capturing a fly 131 I 72. Epigynes of Stemonyphantes lineata and Linyphia INTRODUCTION TO THE ARACHNIDA I montana. Palp of Microneta viaria 134 73· A brood of young Aranea diadema collected in ARACHNIDA is the name of one of the classes in the large characteristic mass 135 74· Epigynes of Oedothorax juscus, 0. retusus and 0. phylum Arthropoda, which also includes the Insecta, the apicatus I3S Crustacea, and the Myriapoda. The name is taken from 75· Young of Aranea diadema 139 the legend that tells of Arachne, the maiden whom the 76. Palp and Epigyne of Gongylidium rufipes- 142 77· Climbing habit of newly hatched spiders - 143 goddess Athena turned into a spider. 78. Aranea reaumuri, Aranea foliata, Aranea raji, The orders into which the class is divided differ a great Aranea sexpunctata 144 deal in size and familiarity. Exclusive of extinct forms 79· Epigyne of Pocadicnemis pumila and Palp and Epigyne of Gonatium rubens these are- So. The first web made by the baby spider Approximate number of SI. Palp of Erigone dentipalpis S2. Aranea diadema showing relative sizes of male and British female Name. Common Name. Species. Species. S3. Epigynes of Hypomma bituberculata, Erigone I. Xiphosura King crabs 5 promiscua, Monocephalus fuscipes and Troxo­ 2. Scorpiones Scorpions 400 chrus scabriculus 3· Pedipalpi Whip-scorpions 50 S4. Male and female Aranea living amicably together 4· Araneae Spiders 20,000 557 on the same web 5· Palpigradi Micro-whip- 85. Palpi of Pachygnatha degeeri and P. clercki scorpions 86. Aranea reaumuri, orie of the largest British spiders 20 87. Epigynes of Zygiella litterata, Z. atrica and Aranea 6. Ricinulei 15 sexpunctata 173 7. Solifugae Wind -scorpions 6oo 88. Web of Zygiella showing the free radius - 180 S. Chelonethi False-scorpions Boo 24 Sg. Palpi of female N emastoma lugubre, Platybunus tri­ 9· Opiliones Harvestmen 2,200 20 angularis and Chthonius ischnochelus - Io. Acari Mites, 1;icks 6,000 ? go. Web of Zygiella, showing the free radius bent out I I. Pycnogonida Sea-spiders 450 22 of the plane of the web !SS gr. Palp of Meta reticulata 1S9 In a general survey, these orders may well be grouped 92. Stemonyphantes lineata, male 198 93· Phalangium opilio : (a) male, (b) female 199 thus- . 94· A freshwater mite 202 A. One order which is marine and in many ways the 95· The Harvest mite Tetranychus. The mites Demodex most primitive- Xiphosura. . caninus and Eriophyes silvicola - 203

I6 B i I, I INTRODUCTION TO THE ARACHNIDA B. Two orders which are sporadically distributed and found only in limited and widely-separated areas­ Palpigradi, Ricinulei. C. Three orders which are confined to the tropical or hot sub-tropical belt, but which are widespread within it­ Scorpiones, Solifugae, Pedipalpi. D. Four orders which are widely dispersed all over the world and thus contain the most familiar Arachnida­ Araneae, Chelonethi, Acari and Opiliones. E. One sub-class which is marine, widespread and in many ways aberrant- . Pycnogonida. Spiders are the dominant group among these orders. There are inore than twice as many species of spiders as of all the other orders together, and they have colonized the whole world, penetrating the polar regions and ascend­ ing the highest mountains, so that spiders are to be found everywhere, even, though exceptionally, in the sea. Hence the bulk of this book will be concerned with them. About sixty British species can readily be found in a single season's collecting in almost any district. If collecting is seriously 'H and energetically carried on the number will soon be 0 0 doubled, but it will be found that many of the captures are 0 very small species and that to name them is a matter of some difficulty. Many of the remainder are rare or local ~ species, and the general naturalist who is not specializing in the group is not likely to meet them often. Nevertheless, spiders will well repay serious study; for our knowledge of their habits and distribution is still far from complete, and there is little doubt that surprises await us. r8 INTRODUCTION TO THE ARACHNIDA False-scorpions are fascinating little creatures which look like minute scorpions without tails. They are widely dis­ tributed and sometimes turn up when the naturalist is searching for spiders, but they are so small and of so retiring a nature that many people have no idea of their existence. The largest of the twenty-four British species is only one-eight of an inch long, but anyone who is attracted by the investigation of small animals will find false-scorpions to provide a very profitable study. Harvestmen, or harvest-spiders, on the other hand, are quite familiar, for, with their long legs and small round bodies, they are common objects of the countryside in late summer and autumn. They are much easier to find and very much easier to name than either spiders or false- . scorpions, and fourteen of the twenty British species are numerous and widely distributed. Thus I have a record of the finding of eleven species in two hours' collecting in Ward's Lane, Aldenham, on Ioth August, I942. Both false-scorpions and harvestmen appear to be wholly devoid of any direct economic importance, so that in study­ ing them one is conscious of the satisfying sensation that one's work is pure Zoology, uncontaminated by any "practical application." But this is not so true of the fourth British class, theMites. Mites are more numerous and much more varied in their mode of life. Some lead a free and independent existence like the familiar little "red-spider " or the many extremely beautiful water-mites. Some are parasites on plants, like the red-currant gall-mites, and many are parasites on animals, like the common sheep­ tick or the minute species which cause Isle of Wight disease in bees. · Mites are, in fact, the only Arachnida which cause I9 INTRODUCTION TO THE ARACHNIDA INTRODUCTION TO THE ARACHNIDA or spread diseases, so that, in one way or another, they frequently enter the field of economic biology. In this and covered by a carapace that is divided by no more than respect it is interesting to notice that mites which are a help an occasional transverse groove. In the abdomen, seg­ mentation can more often be seen. Although the spiders to man, as many insects are, instead of being a hindrance and mites show almost no trace of ring-like structure, or a pest, do not seem to have been evolved. scorpions, false-scorpions and Solifugae are protected above Sea-spiders or nobody-crabs, are found only in the sea, and below by two series of hard plates which make the where they range from the littoral regions to the depths of segmental nature of their bodies quite obvious. In the the ocean. One of their more remarkable features is their harvestmen, segments or grooves which mark them above abundance in the Antarctic, where species with five and and below are clearly visible. six pairs of legs have been found. They creep or swim Limbs of different functions, or appendages as they are extremely slowly, lead a largely parasitic life in association technically called, are attached to many of these somites. with Coelenterates, and their eggs and young ones are The cephalothorax, almost without exception, carries six carried about and guarded by the males. The species pairs. The first pair are situated in front of the mouth actually to be found between the tide-marks of the British and are the jaws or chelicerae. They are composed of two coast, as distinct from those which live in shallow water. or three segments and end either in a single sickle~shaped and can only be captured by trawling, do not number fang or in a pair of pincer-like points. more than ten or twelve. The second pair are called pedipalpi or palpi, and are of It is evident, therefore, that the naturalist who interests diverse functions. In the scorpions, false-scorpions and himself in the British Arachnida has a wide and varied Solifugae they are large and powerful weapons, with pincer­ field of sh:dy. like terminations, and in the false-scorpions they contain GENERAL ORGANIZATION OF THE ARACHNID.-The bodies poison-glands. In Solifugae they are very active· organs, of all the Arachnida are outwardly divisible into two parts­ provided with delicate tactile setae and so essential to the the cephalothorax, also known as the prosoma, and the life of the animal that their loss is fatal. In king-crabs abdomen or opisthosoma. In this respect the Arachnida and Palpigradi they differ so little from the legs that these resemble the Crustacea and differ from the Insects, in which animals may almost be described as possessing five pairs of the head and thorax are clearly separated. walking limbs. In spiders and harvestmen they are tactile Segmentation ~f the body, a conspicuous external feature organs. of many invertebrates, is to a great extent repressed among Four pairs of walking legs are the normal pdssession of the Arachnida. In no order is the segmental character of all the Arachnida. The legs are jointed tubes of chitin; the cephalothorax obvious, and although investigation they end in two or three hard and ·Sharp claws and are reveals a foundation of nine somites, these are closely united richly supplied with spines and setae, as well as providing 20 21 INTRODUCTlON TO THE ARACHNIDA situations for other important sense-organs. In many Arachnida the first segments of the palpi and legs, or soine of them, assist the chelicerae in crushing the captured prey, so .as to squeeze out its body-fluids, which the animal imbibes. For this purpose they are provided with lateral blades or gnathobases, often set with teeth and fringed with "hairs." In some orders the abdomen is joined to the cephalo­ thorax by a narrow waist or pedicle. Spiders, among others, show this feature ; in the rest the somite which the pedicle represents is as broad as its neighbours. The somites of the abdomen, originally twelve in number, do not in general bear limbs in the adult state, although traces of abdominal appendages may be detected in the embryo. The chief exceptions to .this are the spinnerets of spiders, which represent the appendages of the fourth· and fifth abdominal somites. If the above paragraphs have been followed, it will be seen that although a scorpion, a spider and a sheep-tick appear superficially to be very different from one another, their bodies and the bodies of their relatives are all con­ structed on a plan which brings them all within the same zoological class. CoLLECTION.-Arachnida may be caught everywhere at all times of the year, but in the spring and summer young specimens form a large proportion of the catch. The best ways to find them are beating, sweeping and sifting. In beating a good thing to use is an old umbrella, which is held open and upside down under bushes and trees while the foliage above is vigorously shaken or beaten. A shower Pl. 4· B 22 of creatures falls and is caught in the umbrella. I have long Portion of a spider's leg, showing spines and on the upper edge a 22. trichobothrium.~_.:: ~~rtic seta" (.X 30) p. 29. IBIBLOU MUStlJM. . D'Hi!:iT, ATU * INTRODUCTION TO THE ARACHNIDA been accustomed to use in place of an umbrella the object shown in Fig. r. It is very easily made with a wooden frame and a taut canvas bottom. The point is thrust into the bush and the leaves above it are shaken. A feature that is a help is the shape of the wood, a section of which is shown. The arrivals on the sheet run to the sides and,

$et:tion qfframe

. FrG. I.-A Frame of Wood and Canvas for collecting Specimens. meeting the overhanging rim, will usually crouch there instead of running straight over the top. The apparatus is more handy and efficient than an umbrella. I. I·1 I Sweeping is carried out with a stout canvas bag or" net," which is dragged through the undergrowth. The contents are per.iodically turned out on to a sheet of newspaper. or Ii·l the apparatus just described. 11'1 At all times, but especially in winter and spring, numbers .II· I of Arachnida can be caught by sifting. I use a boat-shaped 23 1 '11 ~~~·, I :I INTRODUCTION TO THE ARACHNIDA . INTRODUCTION TO THE ARACHNIDA il!i]'I [1111 sieve of the smallest meshed wire-netting, in which drifted with a piece of cotton-wool and invert it in more alcohol in !li leaves, pine-needles and so on, are shaken over the canvas. a wide-mouthed bottle with a ground-glass stopper. A I Grass roots may be torn up or cut with a strong knife and ,I• label ~hould accompany the specimens in each tube, the ill treated in the same way. data, name, date, locality, etc., being written thereon in :I Beating is not of much value in collecting harvestmen ordinary pencil. It is admitted that glass-stoppered bottles and sweeping is liable to injure them. When, therefore, add very considerably to the expense of making a collection, li/1 these creatures are wanted alive and unhurt it is usually but after many years of experience with various substitutes, i worth while to make patient search among the grass roots, 1: such as "air-tight" tins and bottles with tin screw tops, i! not forgetting how deeply harvestmen may descend, i am convinced that for a collection which is to be per­ il. especially in cold weather. !'11 manent and which may have to survive longish periods of . I Many mites can be found by bringing a boxful of drifted I neglect, nothing but a stoppered bottle is of any value. leaves or similar vegetable debris into the laboratory and ii ' METHODS OF STUDY.-For the examination of Arachnida I !!, I turning it out for inspection on a sheet of paper. Old in order to identify them or to learn the details of their I 11 birds' -nests may also be searched in this way. . I structure, a good lens or a microscope is necessary. High ir Sea-spiders are caught either by turning over stones magnification is seldom if ever needed, and a one-inch or I. between the tide-marks, or, more generally, by trawling 11 half-inch objective will give sufficient help for all purposes. from a boat. It is usual to examine the animal lying in alcohol in a small PRESERVATION.-Arachnida cannot be" set" like butter­ white saucer under a bright direct illumination. Occasion­ flies, and never form· a beautiful collection. Specimens ally it is an advantage to allow the animal to dry and to I which are to be preserved should be killed by dropping I I examine it in the same way without• the spirit. Drying, them into spirit. They must afterwards be kept in spirit I even for an hour or two, will not harm the specimen, which [, which should not be diluted with more than IO per cent. will reabsorb alcohol when retur~ed to its tube. of water, in specimen tubes 2" X. t" or smaller. The more Those who wish to dissect the bodies of spiders or harvest­ brilliant colours may fade, especially the green, but the .men and investigate their internal structure will·find their animal is always available for examination. With large chief difficulties to be the small size of the animal's body spiders the spirit may go brown at first and must be changed and the toughness of the exoskeleton. The latter can only after a few days. be overcome by the use of really sharp instruments ; the As with all spirit specimens there is the danger of former diminishes with practice as the fascination of the evaporation to meet, for corks, even when sealed over with work grows. The mounting of parts or limbs as microscope paraffin wax, are seldom efficient for very long. The only slides does not differ from the mounting of other objects ; really efficient method is to fill the tube with spirit, close it but the popular process of boiling the whole animal in 24 25 INTRODUCTION TO THE ARACHNIDA caustic potash and mounting the empty skeleton is not satisfactory with harvestmen because of the height of the ocular tubercle. An essential part of arachnology is the keeping of live specimens in captivity, to observe their habits and behaviour. Collectors should, therefore, carry a number of small pill-boxes in which living specimens may be brought home. All kinds of spiders do not live in captivity with the same equanimity, but most web-spiders will spin webs in cages and catch live flies and other insects. For cages, . plain cardboard boxes with a glass or cellophane top will serve, but it is always possible to construct more elaborate apparatus, often with profitable results. The addition of · .· ·stones or paper tubes to provide shelter or ready-made ·. burrows is an advantage and a constant supply of water is · necessary for some species. For harvestmen water is an essential and is best supplied in a vessel sunk below a false bottom so that the liquid is level with the animal. If breeding is attempted the cage should also contain a shallow dish of moist earth in which the eggs will be laid. Feeding captive harvestmen is easy, for they do not rieed living food, but will accept almost any contribution from the diriner-table. They may be given cooked mutton or beef fat as well as bread, which, with cold water, are sufficient to keep them in good health. After the females have died the tray of moist earth con­ taining the eggs may be taken from the cage and kept in a covered vessel. It should not be allowed to get too dry. When the young ones appear they may from the first be fed on fat and bread crumbs, but they are not very easy to rear. BRITISH HARVESTMEN back so that they stare sideways with the unblinking gaze of a fish. At the sides, close to the coxae of the second BRITISH HARVESTMEN pair of legs, the openings of a pair of odoriferous glands are visible. These glands, which secrete an irritating or Order OPILIONES nauseous liquid, are characteristic of the harvestmen and are found in no other Arachnida. The glands themselves STRUCTURE AND HABITs.-The body of a Harvestman is can be seen in some species, showing through the carapace not only so characteristic that the animals are easy to as dark spherical objects, recognize ; it is also unique, or at least it is unlike the and more than once they body of any other Arachnid. The cephalothorax is com­ have been mistakenly de­ q,,. posed of six somites and it bears the six pairs of appendages scribed as a second pair '] common to the whole Class. In the abdomen ten somites of eyes. may with difficulty be recognized. There are no append­ The region between the ages ; moreover, the tergite, above, and the sternite, .l ocular tubercle and the below, of the same segment are not always placed vertically fore-edge, which may be opposite to each other. called the clypeus, is This is the unique peculiarity. It may be described by generally covered with saying that the fore-edge of the first sternite has been pointed spines. These dragged forward until it has reached the line of the coxae may be scattered over of the second pair of legs. This has dragged forward the ' • o ! 1 } the area ; but in · the sternites behind it, has brought the anus from its primitive. FIG. 50.-Diagram to compare prim­ sub-family Oligolophinae terminal position to a ventral one, and has bent downwards itive and actual arrangement of three of them are placed Abdominal Sclerites. some of the posterior tergites. In consequence, the tergite conspicuously in front, primitively above the anus now lies behind it, and the ' forming a trident which is characteristic of the group. The sternite primitively below the anus lies in front of it. This relative lengths and positions of the trident spines is often is illustrated diagrammatically in Fig. 50. There· is no helpful in determining the species (Fig. 63). other Arachnid like this. It is the fundamental reason why Fewer features are noticeable on the upper surface of the most Opiliones have short round bodies, while most of their abdomen, where transverse grooves or rows of spicules indi­ allies are long and narrow. cate segmentation. In the families Trogulidae and Nema­ On the upper surface of the cephalothorax the most con­ stomatidae it is covered by a single chitinous shield com'­ spicuous feature is the ocular, tubercle, placed not far from posed of the fused tergites of the cephalothorax and first the fore-edge. It carries two simple eyes, placed back to I3J I36 THE SPIDERS AND ALLIED ORDERS five or six abdominal segments. As a result one finds that the whole dorsal surface can be removed, cleaned and mounted for examination, whereas nothing of the sort is possible with the softer species. There is in many harvestmen a central dark band which forms, as Dr. Cott has recently shown, a good example of that kind of pattern which, breaking up the outline or

2.

FIG. sr.-Pedipalp of Odiellus spinosus.

obvious appearance of the animal's shape, provides it with a degree of inconspicuousness against its natural background. As in spiders, the lower surface of the body shows much more detail than the upper. In front it is composed of the eight coxae, the gnathobases of the pedipalpi and anterior legs and the genital operculum, projecting forwards 3 from the abdomen. This is really composed of the fused sternites of the second and third abdominal segments. The Pl. 74· first sternite is represented by a pair of chitinous plates EPIGYNES r, Oedothora:r fuscus (X 25) p. I I6. 2, Oedothorax re/usus (X 25) I38 p. I I6. 3, Oedothorax 'ea/us ( x 25) p. I I6. BRITISH HARVESTMEN lying in front of or outside the operculum and called the arculi genitales. They are most easily distinguishable in Homalenotus. Four sternites follow the operculum, num­ bers 4, 5, 6 and 7· The arrangement of the eighth and ninth is different in the different families ; the tenth is absent. The chelicerae are composed of three strongly chitinized segments, the third of which works against a prolongation of the second to form a pair of sharply-pointed forceps. There are no poison-glands within; the limbs themselves move freely in a longitudinal direction while the forceps, working transversely, tear to pieces the harvestman's food. The pedipalpi are like short legs. They have six seg-:­ ments-coxa, trochanter, femur, patella·, tibia and tarsus. They are used in manipulating the food and their setae are probably organs of touch. The coxa bears a gnathobase which works against its fellow and helps to crush the food. By the systematist the pedipalpi are used in characterizing the families according to the relative lengths of tibia and tarsus and the character of the tarsal claw when present. Thus- r. No claw Trogulidae and Nemastomatidae z. Toothed claw Sclerosomatinae and Liobuninae 3· Smooth claw. Oligolophinae and Phalangiinae Harvestmen, unlike spiders, do not have the complex sex­ organs in the male pedipalpi, but a hitherto undescribed sex difference is found in nearly all the British species. This is a group of short spicules on the outer side of the male tarsus. The legs are composed of seven segments, the same as !i Pl. 75· I I39· Young of Aranea diadema (X z) p. 130. the pedipalpi plus a metatarsus. The coxae of the first 139 i ]I THE SPIDERS AND ALLIED ORDERS BRITISH HARVESTMEN legs carry gnathobases which assist in mashing the food ; ii. Spines are hollow cylindrical outgrowths, usually the coxae of the second pair also carry gnathobases in some sharply-pointed, such as occur on the hood of Trogulidae, genera, but they do not appear to be normally used in the pedipalpi of Platybunus, and which form the trident of feeding. The other segments sometimes show false articu­ Oligolophinae. lations and this is especially true of the tarsus which, in the iii. Setae are the solid bristle-like objects such as occur longest legs, may consist of more than a hundred pieces. on the legs and are generally more familiar on the legs of The legs all end in a plain claw. Kastner has described spiders, where they are supposed to have a tactile function. how the tarsi may be quickly twisted round grass-stems as iv. Trichobothria (or hairs) are much finer than setae the animal runs; to assist this the cylinders of chitin which and are found on the tarsi and other leg-segments of some make up the tarsus are longer above than .below and a muscle running from the claw to the metatarsus coils up [______the segment.

a FIG. 53· FIG. 52.-Tarsal segments of Phalangi1em. A. Penis of Opilio. B. Ovipositor of Opilio.

In some harvestmen the tibiae of the legs have accessory species; they may be erect or may lie fiat like the true breathing spiracles, leading to the tracheal system. Very hairs of a mammal. In spiders, long erect trichobothria little is known, however, about the respiration of these are supposed to have an acoustic function. animals. The sexes of harvestmen are not very different from each The bodies and limbs of all harvestmen are more or less other. Males as a rule have longer legs. and smaller bodies covered with setae or spines of different appearances, and The sex-organs are not normally visible but they may easily. probably also of different functions. As far as outward be made to protrude by gently squeezing the body, when appearance goes, these dermal structures can be divided they appear at the tip of the genital operculum. The into four groups, which may well be named as follows : ovipositor is a broad tube, the penis is finely pointed. i. Teeth (denticulae or spicules) are more or less sharp It is as a rule only by careful searching that one can conical projections of the exoskeleton, such as occur on the find harvestmen in England in the spring. In March and abdominal tergites of N emastoma. April captures are of three kinds-Nemastoma chrysomelas, 140 141 THE. SPIDERS AND ALLIED ORDERS which can be found at all seasons ; aged specimens of Phalangium opilio or Opilio parietinus, which have had the rare fortune to survive the winter ; and very small speci­ mens of Platybunus triangularis or Megabunus diadema, which have recently hatched. The Phalangium and the Opilio, if brought into the laboratory, prove to be very inactive and soon die of old age. Platybunus and M ega­ bunus evidently pass the winter as eggs. They moult and grow rapidly and are mature in May. By the end of June ·Platybunus is hardly to be found out of doors, but in cages I have kept them alive until rst August. Their place is taken by Liobunum, young specimens of which begin to be seen in early June. They mature by the end of July and are very plentiful in hedgerows during August and September. In the laboratory they survive until January or later. Phalangium appears soon after Liobumtm and is usually the most conspicuous of all British species in the late summer. It seems generally to disappear, often rather suddenly, during October. It is closely followed by Oligolopkus, Odieltus and Mitopus. These species are constantly moulting throughout June, July and August. They are mature in September and October and are the dominant genera of the latter month, but the lower temperatures of November bring them to an enP, out of doors. In cages I have known Odiellus to survive until 26th January. 2 Last of the British species is Opilio parieN12us, which lingers on into November when the rest have disappeared. ···"- --~ -~1-. The hibernation of a few species is interesting : harvest­ PI. 76. I 142. men are much more resistant to cold than to heat. More Gongylidium rufipes (p. I 16). 2;Epigyne (X 20). qz .. BRITISH HARVESTMEN than once I have suffered the accidental loss of captivf: specimens when by inadvertence their cage has been left where the sun could shine upon it. The result is the death of all specimens in a comparatively short time. On the other hand Stipperger records the finding of adult N elima aurantica under snow. Some of these were put out over­ night in a box, the temperature of which fell to - 20° C. The animals became torpid, with their legs stretched verti­ cally upwards in a close bundle, but when placed on her warm hand, they recovered in " ein Paar Augenblicken." I have found similar torpid specimens of Nemastoma chrysomelas in January, which could be instantly re­ I I awakened by breathing gently upon them. Taken indoors they became quite lively and mated with each other as if it had been early spring. The general behaviour_ of all harvestmen is a pattern of reflexes and tropisms with scarcely a suggestion that any consciousness determines their actions. They seem to be even more mechanistic than spiders, for a spider catching a fly or courting a mate does present an outward appearance of purposiveness, which many biologists have liberally inter­ preted, while a harvestman never seems to respond to anything save obviously external stimuli. For example, they are strongly photonegative and collect in the darkest corner of their cage. This is particularly true of the young specimens. Direct light checks move­ ment, so that many species are not active durmg the day; but Mitopus, Liobunum, Phalangium and Megabunus are Pt. 77· I I43· less nocturnal than others. Climbing habit of newly hatched spiders. The egg-cocoon is just Harvestmen also react quickly to the movement of an visible below the spot where the white stone is placed. The young spiders have climbed to the top of the stand. The strips of white image across the retina of the eye. If one's two hands are paper shavings suspended in the silken strands to show tneir course. 143 THE SPIDERS AND ALLIED ORDERS moved up and down at the sides of a harvestman, the animal rises and falls on its long legs in a remarkable and ,, \ rather ludicrous manner. A cageful of Liobunum is par- ~ I . ticularly sensitive in this respect and will react to the move­ ment of one's head as one stoops to look at them. The formerly quiescent creatures are suddenly galvanized into I; ! activity : they race round and round the cage, their bodies rising and falling and striking the box, tap-tap-tap as they go, until after a few seconds they all settle down again into their usual· somnolence. · Harvestmen respond keenly to moisture. They are very dependent on water, and in houses are often found in baths and wash-basins, just as spiders are, attracted there during their nightly wanderings and discovered, unable· to escape, in the morning. Moisture also guides theni to a spot suit­ able for egg-laying; as will appear later. Harvestmen share with many other animals the tendency ·to creep into contact with solid surfaces, called stereo­ tropism, and generally rest in the corners of the cage. The species OdieUus spinosus in particular shows this behaviour, and if there are five or six specimens in a box together they will rest during tl,le daytime all pressed together in a corner. Their response to chemical compounds is also well de\Teloped and occasionally brings harvestmen to the notice of ento­ mologists, for they may be among the visitors to the patches of sugar spread out at night to attract moths. The study of harvestmen is a study of legs. Of the eight characteristically long legs, the first, third and fourth pairs 3 are habitually used for walking, while the legs of the second

pair, which in all British species are the longest, are gener­ Pl. 78. I I 44· ally stretched out in: front, tapping the ground and clearly I. Aranea req,umuri (p. 132). 2. Araneafoliatx (p. 133). 144 3. Aranea raJ~ (p. 132). 4, Aranea sexpunctata (p. 132). ··.•·1 ·,. BRITISH HARVESTMEN acting as organs of touch. A moving harvestman often stops and touches the ground ahead with its second legs before proceeding ; and a resting harvestman may be seen moving its second legs about as if they were constant sentinels against the approach of danger. I have seen a quiescent harvestman respond to the banging of my labora­ tory door by raising its second legs with a sudden jerk. I have seen a thirsty harvestman put its fourth leg into water, turn, and then touch the water with its second leg before moving forward to drink. A harvestman that has lost one of these longest legs does not seem to be seriously · handicapped, but if both legs are lost its behaviour is very different. There are no rapid movements, nohastening to eat or drink or mate. A harvestman so mutilated among a number of others resembles nothing so much as a blind man feeling his way among a crowd of heedless companions. It is a remarkable fact that limbs so vital to the animal's well-being should be so easily lost, and when lost should never be restored. Yet such is .the case. A harvestman sheds its legs on the least provocation, so that it is hardly an exaggeration to say that at the end of the autumn one finds fewer harvestmen with the full complement of eight legs than with any other number. Pickard-Cambridge reported the finding of a specimen that ran rapidly with only two. As has long been known, a leg forcibly pulled off or auto­ tomized continues for some while to jerk spasmodically at the tibial-metatarsal joint. This curious detail has received 3 a delightfully teleological explanation. It is imagined that Pl. 79· K 145· the foe grips the hunted harvestman by the leg, the limb ts r, Epigyne of Pocadicnemis pumila ( x zo) p. rr8. z, 3. Palp and . thus detached, and by its repeated jerkings so occupies the Epigyne of Gonatizmt rubens (X zo) p. I r8. 145 K BRITISH HARVESTMEN THE SPIDERS AND ALLIED ORDERS 11 attention of the predator that the harvestman has time to a scrap of skin left of the abdomen, the legs, chelicerae escape. This is therefore the " purpose " of the jerks ! and pedipalpi were detached and in part sucked dry, and Like spiders, harvestmen carefully clean their legs. A the carapace was polished clean inside. This particular leg is held in the chelicerae, which open and shut as the harvestman ate a second spider six hours later. long joints are slowly pulled through them. By the time Though they appear to be ill-provided with weapons of that the tarsus is reached the leg is bent almost into a attack, harvestmen have a remarkable and efficient method circle, and it finally shoots out like a bent spring. The of defence. The existence of odoriferous glands in the pedipalpi are cleaned in the same way. The chelicerae cephalothorax has already been mentioned, but the fact themselves are largely cleansed by washing in the drinking that their secretion is not very noticeable to the human water, and in a cage food-particles and other debris collect nose prevented for many years a general recognition of their in the vessel, which must be scoured at intervals. function. Simon remarked that the odour was something The food of harvestmen is varied, nor need it be living like that of walnuts ; Rossler detected an aromatic smell at the time of capture. In nature, it would seem probable produced by Opitio albescens, and Bristowe noted that that harvestmen could scarcely rely on finding sufficient some species of the Gonyteptidae possessed " a strong and dead materials to supply their needs, for the dead bodies rather sweet odour." of small animals are uncommon in the undergrowth where Recently the glands and their function have been the harvestmenlive, and no doubt exists that much of a harvest­ subject of a paper by Lawrence. He has observed that man's food has been caught and killed by itself. The some species can either expel the secretion rapidly in the strength of their chelicera! muscles is considerable ; · Riihm form of a fine jet or more slowly, as a large drop accumu­ records that they can easily lift half a gram. lating at the orifice of the gland. He makes it quite clear When the food is obtained the pedipalpi rest upon it, the that secretion is a defence action, a response to irritation chelicerae are sunk in it and slowly move up and down, of the animal either by pressure on its body or by seizing detaching small fragments. Unlike spiders, harvestmen its limbs. Among the European species recorded instances are more inclined to feed little and often, though one meets of thE< use of this gland are few. Stipperger writes that occasional exceptions to this. I have known a young of the many hundreds of harvestmen captured by her, Mitopus, which was evidently hungry when captured, to only one, a male Gyas, was seen to secrete a drop of liquid eat almost the whole of a Ctubionid spider at one sitting from one gland while she held it. An offensive odour lasted and as a result to swell up exactly as a spider would have for two minutes. done in similar circumstances. Another, a male Platybunus, It is possible, but not certain, that the secretion produced to which I gave a dead Lycosa lugubris, spent four hours may be responsible for the anaesthesia which overcomes a 'eating the spider. At the end of this time there was only crowd of harvestmen in some conditions. It is my custom · 146 147 THE SPIDERS AND ALLIED ORDERS when working in the garden to keep an empty jam-pot at hand and to drop into it all the harvestmen that I meet. When these are brought indoors to the laboratory they seem to be anaesthetized, intoxicated or narcotized by each other. While they remain close together at the bottom of l i; the vessel the state of insensibility persists, but very soon after they are thrown out on to the floor of the cage they recover and move away. One of the commonest methods of protection in spiders, the habit often spoken of as " shamming dead," seems to be very rare among harvestmen. I have, however, been told by Dr. R. F. Lawrence that some African species will show this cataleptic state. When grasped by the hand or forceps they become completely rigid. Their legs may then be bent so as to assume the most extravagant positions, which they will maintain for minutes at a time. For example, the legs may all be turned upwards and the animal inverted and stood with its ventral surface uppermost, its body resting on its legs as on a " tripod " of eight parts. At all times harvestmen are subject to the attacks of parasites and to the adherence of passengers which use them as a means of transport. Commonest among the parasites is the :small red mite, Belaustium (Ritteria) nemorum, which often occurs on other animals as well. These mites hold . by their probosces to the body or legs, and often three, four or five mites may be found on the sai:ne harvestman. Internal parasites, such as nematode worms and gregarines, also occur. The phenomenon known as phoresy or the use of other animals as a means of transport is illustrated by the habit Pl. tlo. K q8. of the little false-scorpion Chernes nodosus (p. 184), which The first web made by the baby spider. Its only tuition is that of .148: inborn instinct. It\~ f 1 inch in diameter. i BIBl. llJU ~H,SE:l!M (l~~~"~:~JQ \~$/ BRITISH· HARVESTMEN may sometimes be found holding to the legs of flies. It does not very often make use of harvestmen in this way, but in September 1936 I caught on successive days two specimens of Opilio each carrying one of these small passengers. :I Like spiders and other Arthropoda, harvestmen grow by

a periodic casting of the " skin " or exoskeleton. The i I harvestman hangs itself up by its fourth legs and begins a 0 series 0f convulsive wriggles which split the skin. The "'H chelicerae and the femora of the legs immediately spring out of the gap, followed by the rest of the body, which draws "'.... the legs after it. The final freeing of the legs is done by the X palpi and chelicerae, The former hold the bundle of legs together under the mouth and support the out-drawn limbs; the chelicerae grasp the legs and pull them out, so that the leg-bundle bows out into a circle and all limbs are preened and kneaded by the jaws as they pass. This preening con­ tinues for some hours after the moult is· accomplished. · With a long series of young harvestmen that arrived in a colleague's bathroom during the spring of 1937, I noted that the interval between two moults averaged ten days. Once the animal was seen to be eating its cast skin, but this appears to be exceptional, and is certainly not the custom of harvestmen that are otherwise well fed. Spiders and other Arthropoda often show at the time of moulting the power of regenerating limbs which have been lost. Harvestmen appear to be unique among the Arach­ nida in being unable to recover lost limbs in this way, H 00 Even the short pedipalpi are not reproduced in two or three moults. The wound left by a lost limb is closed and the __j ~ animal remains short for the rest of its life. Stipperger 149 BRITISH HARVESTMEN THE SPIDERS AND ALLIED ORDERS contrary I. have seen two male Oligolophus agrestis approach observes that if the limb is lost at the trochanter in early a female simultaneously, and while one of them mated with . youth, the growth of the coxa ceases and it remains " like he~ the othe~ stoo? by and awaited the opportunity of a thin sausage among its fatter neighbours." If only the which he availed himself as soon as his rival had moved tarsal joints are lost, the rest ofthe leg remains in use. Dr. Bristowe has shed some light on the myth of thes~ It is curious that animals which lose their legs so readily "battles," writing, " In studying spiders' mating habits I should be unable to regenerate them in the same way as did for a brief spell turn my attention to Phalangium to their relatives can.· Probably correlated with this is the see ?ow ~ales reacted to other males. A sort of struggle fact that harvestmen do not themselves remove an injured (wh.Ich might have been described as a fight) took place limb. If a spider's leg is crushed or cut the stump is until one mounted the other. His stimulated condition seized by the chelicerae and pulled off ; but harvestmen supported my . belief that the explanation of the fights do not do this. I have met specimens with injured legs among Arthropods has as its basis sexual excitement and that dragged helplessly and hampered the animal's move­ shall we say, mistaken identity. The male's chemo-tacti~ ments, but which were never amputated. sense is stimulated not only by a female but also by a male ' One of the most striking differences between spiders and of its own kind." harvestmen lies in the relation between the sexes. Spiders Har:estmen are known to lay their eggs undergroun·d. mate rarely and give us the impression of a serious process, Early 111 August 1935 a harvestman in one of my cages laid not witho~t risks, to be undertaken only after elaborate her eggs in the water provided for drinking, and this fact courtship. Harvestmen mate freely and frequently, even led me to believe that oviposition is stimulated by moisture · in captivity ; there is no courtship either visual or tactile, in. much the same way as several malodorous compounds and the sexes unite almost as soon as they meet. Their ~hmulate egg-laying in blow-flies. Accordingly, I placed union occupies only a few moments, and both partners, 111 the cage a shallow tray of moist sand and by the end of wandering on, are likely to mate again, either with each the month found that three batches of eggs had been laid other or other inhabitants of the cage. The species of under the sand. Oligolophus are particularly insatiable, and when well fed The females usually die very soon after they have laid spend the evening in no other occupation. their eggs, but the males survive them. Simon in 1879 reported that at the breeding season the The eggs are pale-green spheres, rather less than half a males fight "bloodless battles" with each other, and this millimetre in diameter, not adhering to each other and not has been repeated several times by other writers. I have covered or protected in any way. I have found that eggs never yet witnessed anything of the kind in my laboratory, of Odi.ellus spinosus laid in November hatch early in the even when the number of harvestmen in a cage gave oppor­ followmg February, producing tiny harvestmen, their bodies tunity and encouragement for such a display. On the I5I :! I 50 THE SPIDERS AND ALLIED ORDERS BRITISH HARVESTMEN smaller than a pin's head. I have fed them on moist bread­ Fainily-Trogulidae Sub-family-Oligolophinae Trogulus tricarinatus (T. 111itopus moria (Ol. al-. crumbs and mutton fat, which they ate, but they seem to rostrattts) pinus ; Ol. cinerascens) be difficult to rear. The records of six specimens are A nelasmocephalus cam­ Oligolophus agrestis appended as an example- bridgei Oligolophus tridens 6. Family-Nemastomatidae OligoloPh.us hanseni I. 2. 3· 4· 5· Nemastoma lugubre (N. Odiellus spinosus Hatched 5 Feb. 5 Feb. 5 Feb. 7 Feb. 7 Feb. 7 Feb. 1st moult 25 Apr, 25 Apr. 24 Apr. 28 Apr. 3 May 6May bimaculatum) Odiellus palpinalis 2nd moult 9 June 5 July 28 May 16May Nemastoma chrysomelas Odiellus meadi 3rd moult 2 Aug. Family-Phalangiidae Lacinius ephippiatus (Oli~ Died 28 June 3 Aug. 4 May 7 May Sub-family- Sclerosoma­ golophus vittiger) tinae Sub-family-PhalCmgiinae CLASSIFICATION.-The two thousand known species of · H omalenotus quad1•ident- 111egabunus diadema (M. harvestmen are divided into three sub-orders, only one of atus insignis) which, known as the Palpatores, is represented in the Sub-family-Liobuninae Platybunus triangularis British fauna. It has been divided into two tribes, Dyspnoi Liobunum rotundum (P. corniger) a:nd Eupnoi, the former of which contains four families, Liobunum blackwalli Phalangium opilio Nelima silvatica Opilio parietimts (Ph. ii two only of which are British, and the latter one. The saxatile) separation of our harvestmen into families is therefore an !I easy task, accomplished thus- TROGULIDAE I I (z) Tarsus of pedipalp shorter than tibia; pedipalpal The Trogulidae are the most primitive harvestmen found claw absent ; second legs without gnathobases ; legs in this country. They have always been described as very without stigmata-Tribe Dyspnoi. 3· rare, but they lead inconspicu­ 2 (r) Tarsus of pedipalp longer than tibia; pedipalpal claw ous lives generally in chalky well developed, second legs with gnathobases ; legs with places. A sufficiently careful stigmata on tibiae-Tribe Eupnoi. search among fallen beech PHALANGIIDAE (p. I59)· leaves would almost certainly 3 (4) Cephalothorax produced forwards into a bifurcated reveal them in many localities ·hood covering chelicerae ; eyes level with carapace. in the south of England. TROGULIDAE (p. 153). The chief outward character 4 (3) Cephalothorax with no such hood ; . eyes on ocular of the family is, as mentioned tubercle. NEMASTOMATIDAE (p. r56). above, the existence of a hood FIG. 54.-Hood of Anelasmo­ The following is the list of the twenty British species­ extending forwards from the cephahts. I52 153 THE SPIDERS AND ALLIED ORDERS BRITISH HARVESTMEN cephalothorax and covering the chelicerae and palpi. . Opiliones and their tarsi are composed of 2, 2, 3 and 3 pieces There is no ocular tubercle, the eyes lying flat on the surface only (Fig. SS). The coxae are immovable and all are fused of the carapace. together, forming a strong, nearly semicircular piece on The body is protected above by a shield formed from the each side of the lower surface. Those of the first legs carry fused tergites of the cephalothorax and the first six segments gnathobases separated from the fixed part by a strip of of the abdomen, the posterior edge of the sixth forming softer membrane which gives them some mobility. The the apparent end of the body as seen from above. The second pair of coxae have no such gnathobases. seventh tergite is a narrow transverse strip forming the The reproductive organs are also different in this family. posterior surface ; the The ovipositor is a short broad tube, without the rings that eighth and ninth lie at characterize it in the Phalangiidae, and terminating in a the sides of the anus, pair of very short forceps. The penis has not the so-called forming with the " glandular " part at the end. · small oval tenth part There are two British genera, easily distinguishable. . > of the .corona analis. _ On the ventral side r (2) Hood of large semicircular plates, with small spines < the first abdominal on outer edge. Trogulus. sternite is a small ves­ 2 (r). Hood of small projections, with long cylindrical tige dorsal to the geni­ spines. Anelasmocephalus. tal operculum, which Troguhts tricari1zatus is 6 mms. long, its body narrow and is composed of the 3 flattened, with short FIG. 55.-Tarsi r, 2 and 3 of Trogulus. second and third ster­ rather robust legs. Its nites. This is followed general colour is :(_) by four normal and separate sternites, numbers 4 to 7· brown, but the tarsi The eighth and ninth form a narrow plate in front of the are darker. The single f0 anus. The tenth is missing. shield over its dorsal The chelicerae are smaller than in the other families ; the surface and the con­ second segment is directed almost horizontally instead of cealment of the cheli- vertically, as is normal ; and the pedipalpi show the char­ cerae and pedipalpi FIG. 56.-Pedipalp of Trogulus. acteristic of the tribe Dipnoi in having a short tarsus with­ under the hood makes out a claw (Fig. s6). this species and the next unlike the other British harvest­ The legs are much shorter than is usual among the men in general appearance. In addition it moves slowly IS4 rss THE SPIDERS AND ALLIED ORDERS and is habitually covered with pieces of dirt. The younger stages are a striking violet colour. It occurs only in the south of England, save for a single record from Buxton. It is commoner in Europe. Anelasmocephalus cambridgei is a smaller animal, 3'5 mms. long, darker in colour and not so flattened in appearance. It has the same general appearance as Trogulus and is just as dirty. Both these species are probably to be found in the adult state at all seasons. Records of Anelasmocephal~ts have come from the south.:-coast counties as well as Surrey, Warwick and Derby, and from North and South Wales.

NEMASTOMATIDAE The N emastomatidae are more closely related to the Trogulidae than to the Phalangiidae, a fact which is ex­ pressed by uniting them in the tribe Dysl:moi. Neverthe­ lessthe two British species bear superficially a closer resem­ blance to the common Phalangiidae than they do to the rarer Trogulidae, for they lack the forwardly directed hood, they have longer legs a:nd their eyes are borne on an ocular tubercle. Moreover, the second segment of the chelicerae is vertical and not horizontal. Their abdomens, however, retain nine tergites and ten sternites ; the last three tergites are free, while the rest are united with those of the cephalo­ thorax to form a continuous dorsal shield, and the corona analis consists of four sclerites, as in the Trogulidae. Also as in that family the pedipalpal tarsus is shorter than the tibia and has no terminal cl~w ; while the genitalia show the short ovipositor and immovable glans penis (Fig. 57)· The structural features which are characteristic of the family are the large size of the genital operculum, the PI. Sz. K 156. I 56 . . . Amnea. diadema • iBIBL.ou Showmg relahve s1zes of male (above) and female (X 3 ) p. 130. 1.4\IJSF.I!M ··~~~~:~!~~I;~ "-

) i ately after a casting of the skin the new setae are of ordinary ;i appearance, and the spherical tip appears only after the lapse of time. In­ cidentally, too, the / knob is invisible on limbs mounted in 2 Canada balsam-evi­ dently the substance of which they are composed has the same refractive FIG. 57· A. Ovipositor of N emastoma. index. B. Penis of Nemastoma. ·The genus N ema­ stoma is divisible into two groups : the species in one group 3 are black and rather short-legged, in the other group the legs are longer and the colour is the more usual brownish. The two British species belong one to each group. Nemastoma lugubre. The general appearance and colour­ ing of this species make it immediately recognizable. Its small rotund body, 2·5 mms. long, with rather short legs, and its prevailing black colour with two large white patches on the cephalothorax, are quite distinctive. In some speci­ mens the patches are pale yellow, sometimes they are K I57· cream-coloured and sometimes silvery. The abdomen is EPIGYNES 157. I, Hyponpna bituberculata (X zo) p. I I9. 2, Erigone promiswa ( x zo) p. I20. 3, Monocephalus juscipes (X zo) p. I2I. 4, Troxo­ chrus scabriculus (X zo) p. I2I. THE SPIDERS AND ALLIED ORDERS BRITISH HARVESTMEN very hard above and bears transverse rows of small blunt golden spots and carrying denticulae on their hinder edges. denticulae or granulations, marking the hind edges of the The legs are relatively longer than those of the last species. tergites. The legs are strong ; in colour they are dark with N emastoma chrysomelas may be found in the adult state paler metatarsi and tarsi. at all times of the year, even in midwinter. It occurs all Another characteristic is a over England, 'has been recorded from Inverness and in blunt process on the first Wales accompanies N. lugubre to the tops of the mountains segment of the chelicerae of of Snowdonia. There is only one record from Ireland. the male (Fig. 58), which Abroad, it extends all over Europe. makes it possible to distin­ guish the sexes with ease. PHALANGIIDAE This harvestman is found The remaining sixteen British harvestmen belong to the tribe Eupnoi or the co-extensive family Phalangiidae. The b everywhere in the British a Isles, including the Channel most obvious feature which distinguishes the group is the Islands, the Orkneys and length of their legs. The legs of the second pair, which are several ·other small islands. always the longest, are at least five times as long as the FIG. sS.-Chelicerae of Nema­ body, sometimes seven or eight times as long, and in a few stoma. It also occurs on the tops of (a) lugubre; (b) chrysomelas. mountains at heights above species even more than this. In addition these legs as well 2,500 feet; and abroad it as those of the first pair carry large gnathobases which are extends over the whole of Europe from the Arctic to the rudimentary or absent in the Dyspnoi. Mediterranean. More careful examination shows a further reduction in N emastoma chrysomelas. This species does not seem to the number of visible somites. On the dorsal surface of resemble the last very the abdomen eight tergites only are present, followed by closely, but like it, it is the anal operculum : on the ventral surface there are five easy to recognize. Its body sternites behind the genital plate. These are numbers 3 to is 3 mms. long, but its pedi­ 7, and the edge of the seventh borders the anus, which is palpi are twice this length, terminal and not ventral. The first five tergites are more or less closely united ; the last three are free and can often a peculiarity which makes FIG 59.-seta of N. chrysomelas. it at once identifiable. The be seen to be distinct and to form as it were a short tri­ peculiar knobbed. setae (Fig. 59) on the pedipalpi have been angular " tail.''. This, however, depends on the sex of the mentioned above. The dorsal sclerites of the abdomen are animal, the state of repletion or hunger, and on the develop­ a rich yellow-brown colour, dotted with small silvery or ment of the eggs in the ovary I 58 159 THE SPIDERS AND ALLIED ORDERS BRITISH HARVESTMEN In addition to these, the claw on the palpal tarsus, the clearly to' be seen in this group, where it is represented by teeth or setae on the palpal femur and' the spur on the two plates of chitin in front of the genital operculum. The first segment of the chelicerae are features which are cu.rious row of four blunt tubercles on the posterior edge important because they are used in separating the four of the fifth tergite make the sub-family unmistakable. sub-families which the group contains. Homalenotus quadridentatus (Fig. 6o), our only species of The following table separates the Phalangi-idae into its the sub-family, is recognizable by the characteristic pattern, four British sub-families- composed of four rows of dark squarish spots each with a lighter tubercle in the middle. ! (2) Pedipalpal claw toothed. 3· The two central longitudinal 2 (r) Pedipalpal claw smooth. 5· rows, each of four spots, are 3 (4) Abdomen with four teeth on posterior margin ; open­ generally more clearly marked ings of odoriferous glands hidden by first coxae ; anus than the row on each side, visible ; gnathobases of second legs far apart. which also consist of four spots. ScLERosoMATINAE. Besides the four posterior 4 (3) Abdomen smooth posteriorly ; openings of odor­ tubercles, there is a central beak­ iferous glands visible ; anus hidden ; gmi.thobases of like tooth on the fore-edge of second legs in straight line ; legs very long. the cephalothorax : in some LIOBUNINAE. specimens it bears small lateral 5 (6) First segment of chelicerae with ventral tooth or spur; spines, The setae on the legs ante-ocular region with a trident of three conspicuous are broad and blunt, rather more spines ; gnathobases of second legs forming an obtuse like blades than spikes. angle 0LIGOLOPHINAE. FIG. 6o.-Homalenotus A variety, formerly described 6 (5) First segment of chelicerae without spur ; ante- quadridentatus. as a separate species, Sclerosoma ocular region without trident. PHALANGIINAE. Romanum, has sharper t~bercles on the abdomen, spines ScLEROSOMATINAE on. the tibiae, and a second tooth, directed downwards, This sub-family, though rightly placed among the Phalan­ below the beak of the cephalothorax. giidae, resembles in certain ways the families of the Dyspnoi. This is a southern species, on record for ten English For example, the cephalothorax and first five abdominal counties of which Worcestershire is the most northerly. It segments are covered by a single shield and the segments has not been found in Ireland or Wales. It also occurs in behind the fifth are sharply bent down to form the posterior South Europe and. in North Africa. and part of the ventral surface. The true first sternite is r6o I6I L THE SPIDERS AND ALLIED ORDERS BRITISH HARVESTMEN Liobunum blackwalli is closely allied to the foregoing, but LIOBUNINAE the body of the female is usually a little smaller. It is In this sub-family the length of the legs reaches a maxi­ easily distinguished from it by a white line or band which mum ; for example, the body of a male Liobunum rotundum runs forward from the ocular tubercle to the edge of .the is 3 or 4 mms. long and the second leg is about 6o mms. cephalothorax, and, more conspicuously, by a white band long, or nearly twenty times the length of the body. The encircling each eye. The abdominal markings of the female segmentation of the abdomen is almost indistinguishable, are like those of L. rotundum, but the ground-colour is often .as the exoskeleton is smooth and devoid of all but the brighter. I have known specimens so bright that at a little smallest denticulae. The ocular tubercle is smooth and distance they were at first mistaken for ladybirds. .spineless. The claw of the pedipalp, as in Homalenotus, is The species appears to be almost as widespread as L . rotundum, but its actual records are not so numerous. It toothed. The two British species of Liobunum are very common is found in Western Europe, but not in Africa. in long grass in early autumn, and a striking feature is the N elima silvatica is a rare species which resembles the speed with which they move. A harvestman when once common Liobunum closely enough to make it at once seen does not often evade capture, but Liobunum requires obvious that it belongs to this sub-family. It can be dis­ .closer attention than any other. No harvestmen live com­ tinguished from the two foregoing species by a dark spot munallives, but Liobunum in particular is liable to congre­ at the distal end of each coxa, by its pale trochanters with­ gate in numbers where the conditions are favourable. In out lateral teeth, and by the two rows of small denticulae Devon I have found clumps of thirty or forty individuals, on the ocular tubercle. ·:none of them paying much attention to the others. A single male was found by Dr. Jackson at Minehead'in 1938 ; previously the only British records were from the Liobunum rotundum is at once betrayed by the length 'i, ,of its black legs. The body of the female, 5 to 7 mms. islands of Skokholm and May, where it was found by long, is a smooth oval shape, brown in colour, with a dark Bristowe. median dorsal band which iis broadest posteriorly. The 0LIGOLOPHINAE .ocular tubercle is smooth and each eye is surrounded by a black ring. The body of the male is smaller and more This group, characterized by a small ventral tooth on rounded, and its uniform red-brown colouring is unrelieved the basal segment of the chelicerae (Fig. 61) and a trident by any median or other marking. of spines near the front of the cephalothorax, is the largest This species occurs all over England, Wales and Ireland, of the British sub-families. Its eight species include some .as well as the Channel Islands ; and extends to the Canaries of the commonest of our harvestmen, as well as the only ones which require fairly minute examination to determine .and to Africa. 163 TBE SPIDERS AND ALLIED ORDERS the identity of the species. Moreover, some of the specific features are developed only when the animal is mature so that, as is usually the case with spiders, immature specimens may be difficult to name. The four genera of the sub-family can be separated by the following table-

I (z) Femora of pedipalpi with ventral spines or teeth. 3· 2 (r) Femora of pedipalpi ventrally only hairy. 5· 3 (4) Femora and tibiae of legs strongly toothed. . Lacinius. 4 (3) Femora and tibiae of legs only hairy. OdieUus. 5 (6) Trident of small blunt tubercles. Mitopus. 6 (5) Trident of large sharp spines. Oligolophus. Mitopus morio is a very distinctive animaL The female, which is 8 mms. long, is of a creamy yellow colour and the median dorsal band is deep brown or black. This band is produced forwards along the centre of the cephalothorax, where it is wider in front. The two portions of the band thus produce an hour-glass-like pattern ·which it is not difficult to recognize. It often has a pale median longi­ tudinal stripe. The leg~ and pedipalpi are dull yellow with brown marks. The femur of the pedipalp bears a short blunt apophysis, covered with setae. The ocular tubercle slopes slightly backwards and the spines of the trident are very small. The male is 5 mms. long and squarer in appearance. Its Jpgs and pedipaJpi are much darker than those of the female ~nd the whole creature is more nearly black in colour, save ·for its transverse rows of white abdominal denticulae. In 164 BRITISH HARVESTMEN fact the sexes differ more in this harvestman than in any other British species. I I. Two varieties of Mitopus morio have been described under

different names. The earlier of these, alpinus, is an upland 1: variety in which the first tibiae are more strongly armed I with spines and the third I:. I metatarsi in the male are ,1' ].: thickened in the middle. The other, cinerascens, has no spines on its legs and the I

dorsal band is longitudinally II, divided by a pale strip. Mitopus morio is found all over the British Isles as far as the Orkneys. It reaches the summits of our highest mountains, is the only harvestman recorded from Fro. 6r.-Chelicera of Mitopus, Greenland, and also exists showing tooth on first segment. in Iceland and Spitzbergen. It crosses the whole of Europe to Siberia and on to China and Persia, and is also found in North America. Oligolophus agrestis is an extremely abundant species and easy to identify. Its abdominal pattern is based on a greyish or silvery background, with brown and often reddish markings. The median dorsal band is usually well-defined and has yellow, brown or red edges. It is this tendency to a red colour that provides the first means of identification. ',I On the lower side the genital operculum supplies the second, Pl. 85. L r6s. a small semicircular notch on its anterior margin, as if a PALPI bite had been taken out of it (Fig. 62). The legs are not 1, Pachygnatha degeeri (X 25) p. 124. 2, Pachygnatha clercki (X 25) p. 12+ r6s BRITISH HARVESTMEN THE SPIDERS AND ALLIED ORDERS . Odiellus spinosus is a most interesting species, recog-­ long and their femora are rounded, a fact which helps to mzable at a glance. Its body is large, 9'5 mms. long in I' I distinguish this species from the next. The trident of the fei_Uale, 7 mms. in the male, and broader in proportion spines, a feature of this sub-family which is a great help in J· than 1s customary, so that the animal has a flattened distinguishing the species, is described in a comparative · i ' appearance, similar to that of crab-spiders (p. 56), as if it I I .. I riote below. were accustomed to hide itself in crevices. The three spines I' i of the trident are broad, bluntly pointed and lie almost horizontally, projecting forwards over the edge of the Ii I• cephalothorax from a small area of chitin, which is readily I,,, 11 I' separable from the rest of the carapace. The denticulae on I' I I the ocular tubercle are very small. The median band on. I FIG. 62.-'Genital operculum of Otigolopltus agrestis. the abdomen is sharply and squarely terminated behind. This is a southern species, its most northerly record so This species is widespread all over Britain, and in Europe far being Leicestershire. It is a peculiar creature, more generally. · often found in gardens and cultivated places than in wilder Oligolophus tridens is as abundant as the last species, to surroundings. It extends to Spain, Italy and Algeria. which it is closely allied : ·.the two are often found in com­ Odiellus palpinalis is much smaller, the female being only pany, but in wet places tridens is the more frequent. It 5 mms. long, the male 3'5 mms. The median dorsal band is very slightly larger than agrestis, is duller in colour is broad and has almost parallel sides-it is obsolete in some without the red tinge in its markings, and the genital specimens-and the abdomen on which it lies is quite operculum is smoothly rounded in front. The femora of smooth. The short legs are of a pale yellow-brown colour,. its legs are angular. ringed with darker bands-an obvious recognition-mark. This species is as widespread as the above. The pedipalpi also help to determine the species, for the Oligolophus hanseni, the third member of the genus, is patella has a short apophysis, covered with setae. The not so commonly found nor so widely distributed. It is denticulae on the ocular tubercle are long and pointed. about the same size as the other two, the female being about English records of this species extend from Yorkshire to 6 mms. long, the male about 4 mms. It has the rounded Dorset, but it has not been found in Scotland, Wales or genital operculum of tridens and the rounded femora of Ireland. agrestis, and is lighter in colour than either. Odiellus meadi, the smallest of the genus, is 3·7 mms. There are not many known British localities for this long in the female, 2 mms. in the male. The median dorsal species, but they extend from Yorkshire to Surrey. It has band is often composed of a number of confluent spots and also been found in Lanark and Guernsey. 167 !66 THE SPIDERS AND ALLIED ORDERS BRITISH HARVESTMEN the abdomen, in contrast to that of palpinalis, has a con­ a straight line. In Odiellus meadi the central spine is twice spicuous row of strong white teeth on the hind edge of as ~ong as its neighbours; in the rest it is but slightly longer; each segment. The trident has a very long central spine. Ohgolophus hanseni has a spine on each side of the trident This species is on record for Dorset, Kent, Sussex and· as well as a sixth just behind it. To distinguish Oligolophus !:·:' It I' Cheshire. has been found in Guernsey, but notin Europe, 1'1 i and is the only harvestman peculiar to Britain. -Md- ::i! Lacinius ephippiatus is between 5 and 6 mms. long. It ~' : I ·I bears a more distinct pattern than most, for its abdomen ::,1 is a creamy yellow, bearing a strongly-marked median band '·': i of dark brown or black with parallel sides. The band is sharply and squarely truncated behind, as in Odiellus FIG. 63.-Tridents of: spinosus ; and in fact the two species bear a distinct general spinosus palpinalis tridens resemblance, as if one were a smaller edition of the other. agrestis meadi hanseni This species may be further identified by the very small tridens from Odielhts palpinalis the branched pedipalp and size of the denticulae on the ocular tubercle, and, in addition, the lo~~ ocular tubercle spines of the latter are helpful. the femora, patellae and tibiae of the legs are darkened at I~ addthon the setae on the pedipalpal tibia of palpinalis their distal ends. anse from small protuberances of the exoskeleton. Lacinius has a wide distribution in England, Wales and Ireland. In Europe it reaches Austria and Italy. PHALANGIINAE Note on the Tridents of the Oligolophinae. As stated This sub-family contains the largest and the best known above, the differences in the form of the trident provide species in our fauna. Its distinguishing features include valuable help in characterizing the species of this group. In the smooth claw on the pedipalpal tarsus, the absence of two species, Mitopus morio, with it strident of small widely­ a trident, and the absence of a ventral tooth on the first separated spines, and Odielhts spinosus, with broad horizontal segment of the chelicera. The four British species all spines, the distinctive character is obvious under a hand belong to different genera, which may be separated thus- lens. For the other six species a microscope is helpful. The central spine is .situated slightly in advance of the ! (4) Tibial segment of pedipalp with apophysis. 2. two lateral spines in Oligolophus agrestis and Lacinius 2 (3). Ocular tubercle with· two rows of five very long ephippiatus. In the former species the central spine is spmes. Megabunus. slightly the longest ; in Lacinius they are equal in length. 3 (2) Ocular tubercle with normal spines.. Platybunus. In the four remaining species the three spines are set in 4 (I) Tibial segment of pedipalp unbranched. 5. r68 169 THE SPIDERS AND ALLIED ORDERS BRITISH HARVESTMEN

I' 5 (6) With median dorsal band ; male chelicerae with horn thorax are few and small. The underside is a pale yellow. i : on second segment. Phalangium. The legs are moderately long and are pale brown with black I I I r 6 (5) With median dorsal spots ; dark spots on underside tarsi. Its most characteristic feature is the form of the of coxae. Opilio. pedipalp (PI. 89). Both the patella and tibia are prolonged (1! into bluntly-pointed apophyses and these two projections I, I Megabunus diadema is a small species, 4 mms. long, ~ith at once determine the species. lr I' f two fP-::ttures which make it unmistakable. Its abdommal The variety originally described as Platybunus corniger is I pattern lacks the normal central rather larger, smoother and with a less defined band on the I::, mark and bears instead a pleasing abdomen. The denticulae on the ocularium are sharper and ,j' mixture of silver, black and green more numerous and the pedipalpal apophyses are shorter. :I'I, which, though not easy to des­ This species is to be found all over Britain and from :, cribe, is quite distinctive. But Scandinavia to the Balkans. more conspicuous is the ocular Phalangium opilio (PI. 93) is the large common species so tubercle in the centre of the conspicuous in the autumn, and is often enc<;mntered run­ (1 cephalothorax (Fig. 64), for it is ning across lanes or fields or in gar­ ). armed with two rows of very long dens. The female may reach 9 mms. 1 FIG. 64.-0cularium of sharp spines. It appears that in 1 Megabunus diadema. in length, the male varies from 4 to 7 .I some specimens the fourth of mms. The colour of the species is I these spines is clearly shorter than the rest, and this greyish, yellowish or brownish, gener­ variety was at first descriped as a different species under ally with a well-marked dark-brown the name Megabunus insignis. median band with angular margins. This species, like the following, is to be found mature in Very often this band is broken by a the spring. It is widely recorded from England ~nd pale median stripe. The underside is Ireland, but has not been found in Wales. Its fore1gn white or grey. The legs, which are records come from France and Norway. yellow-brown, have angular femora FIG. 65.- Chelicera Platybunus triangularis, even apart from its being the only armed with rows of sharp teeth. of male Phalangium opilio. large harvestman to be found in the spring and early The male is a very distinct animal summer, is easy to recognize. Its abdomen is a dull-yellow with a smaller abdomen and usually with no trace of a colour with a dark-brown median band, on each side of median band. Its pedipalpi are much longer than those which there are· two or more white spots in each segment. of the female. Its conspicuous feature is the large dorsal It is quite smooth and even the denticulae on the cephalo- horn on the second segment of the chelicerae (Fig. 65). 170 171: THE SPIDERS AND ALLIED ORDERS This curious projection varies somewhat in size and shape in different individuals, but it is a .possession shared by no other British harvestman. The species is ubiquitous in Britain and the surrounding islands, from Russia and Siberia to central Asia and North Africa. Opilio parietinus is a large species, the female 7'5 mms., the male 6·o mms. in length. It has a grey-brown mottled appearance due to a mixture of yellow, white and brown spots. There is no dark median band but a longitudinal row of brown dots sometimes takes its place. The legs are long and spotted and the distinguishing feature of the species is an elongated black or dark brown spot on the underside of each coxa. The ovipositor of the female is unlike that of the other British species: it is conspicuously · marked with a number of dark angular rings (Fig. 53). The variety previously described as Opilio saxatile is smaller and carries a row of white spots on the middle of the abdomen. Its habits are not quite the same as those of parietinus. Some have regarded it as an immature form, but adults certainly exist. It has not, however, been possible to find any constant distinguishing feature between the two. This species is widely distributed in Britain and Europe and is also recorded from North America.

172 SHORT BIBLIOGRAPHY OF BRITISH HARVESTMEN

R. H. Meade, 1855· "Monograph on the British Species of Phalangiidae or Harvestrnen," Ann. JYlag. Nat. Hist., pp. 393-416. R. ·H. Meade, r86r; " Supplement to a Monograph on the British Species of Phalangiidae," Ann. Mag. Nat. Hist., pp. I-5· 0. Pickard-Cambridge, r89o. "Monograph of the British Phalangidea or Harvestmen," Proc. Dorset Field Club, xi, pp. 163-216. J. E. Hull, 1926. "British Harvestmen," Vasculum, xii, pp .. 124~33· T. H. Savory, 1938. "Notes on the Biology of Harvestmen," ]. Quekett Mic1•os. Club, 4, I, pp. 89-94.

2 E. Simon, r879. Les Arachnides de France, Tome VII, pp. rr6-3rr, Paris. C. F. Roewer, 1923. Die Weberknechte der Erde, Jena. A. Kastner, 1928. Die Tierwelt Deutschlands, VIII, pp. r-51. H. Stipperger, 1928. Biologie der Opilioniden Nordtirols. Zool. Inst. Univ. Innsbruck, iii, pp. 19-79.

, ______

3

L I73· Pl. 87. EPIGYNES r Zygiella litterata (X 15) p. r 30. z, Zygiella a11•ica (X rs) P· rzg. 173 ' 3, Aranea sexpunctata (X rz) p. 132. BRITISH FALSE-SCORPIONS· true scorpion, for they have no tail with terminal poison­ sting at the end of their bodies. In front they resemble BRITISH FALSE-SCORPIONS scorpions more nearly, for they have small chelicerae and Order CHELONETHI very large prehensile palpi, which form their chief weapons. The cephalothorax is uniformly covered with a more or THE false-scorpions, which form an Order of Arachnida less rectangular carapace, which, as in spiders, conceals the known as Pseudoscorpiones or Chelonethi, are small animals segmented character of the body. The carapace bears the which lead obscure lives in dark places. As a result they eyes of which there are primitively two pairs, although some are often quite unknown even to those who look upon both species have but one pair and some are blind. spiders and harvestmen as familiar, for they are encountered There is no pedicle ; only a groove separates the cephalo­ only when they are deliberately sought-and not always thorax from the abdomen. The latter is clearly segmented then ! The largest false-scorpion in the world is an Asiatic and composed of twelve somites, much more clearly dis­ species 6 mms. long. The twenty-four British species range cernible even than in the harvestmen, for there are eleven from 3·6 mms. to r·r mms., a fact which by itself is enough separate tergites and eleven sternites. The twelfth tergite to ensure their general neglect. It is indeed the only and sternite are joined together and form a circum-anal ring. possible reason for it, for there are few more interesting The first sternite is often reduced or fused to the second, animals in the world. forming a genital operculum, behind which is the genital False-scorpions are to be found by searching in damp or aperture. dim places where vegetable debris accumulates-the same On the lower surface the coxae meet in the middle line, so places where, in fact, one finds many of the smallest spiders, that there is no sternum, at least in British species. There under stones and the dead bark of tree-trunks, among moss, are no true gnathobases on the legs. The fourth pair of in dead leaves and the other materials at the base of hedges, .coxae project backwards and to some extent displace the in rubbish of all kinds, in heaps of manure, on the sites of old first and second sternites, so that they do not correspond haystacks, in haylofts, in crevices and under bits of wood in with the tergites. It will be seen that this distortion has old buildings, stables, and sheds. Although they are so taken place in the opposite direction from the forward dis­ small, they are very easily recognized when, in beating or placement noted in the harvestmen. It is also · much sifting, they fall with so much else upon the sheet, for they slighter and after the fourth segment the tergites and have a squarish or rectangular mien ; they generally crouch :sternites correspond. motionless until they are touched, and then they at once These chitinous plates are set in a softer pleural membrane proclaim their nature by running backwards. which is very elastic. It contracts during starvation and They bear only a slight and superficial resemblance to the stretches when the animal is well-fed or distended with eggs : I74 I75 THE SPIDERS AND ALLIED ORDERS BRITISH FALSE-SCORPIONS in consequence measurements of length are of uncertain minal tooth are present in either the fixed or the movable value in false-scorpions. In some species the plates are con­ finger or in both, and false-scorpions, like spiders and unlike tinuous transverse strips, in others either the tergites or the harvestmen, are therefore venomous arachnids. Their sternites are divided medially into right and left halves. poison is, of course, harmless to man, whose skin they cannot The small chelicerae (Fig. 66) consist of two segments pierce, but it is presumably lethal to the animal's normal only, the second moving against a projection of the first. prey. These important organs are also interesting because They form, as it were, the hands of the animal used in hold­ there is such a wide range of variation in their proportions ing food, in carrying it about and in picking up grains of that the pedipalp of every species is probably unique and sand or other particles used in nest-building. Hence their distinctive of the animal that uses it. pincers are toothed. They act as spinning organs, produc­ The legs are not very long, and are composed of eight ing a silk thread through a spinneret segments. The tarsi end in a pair of sharp curved claws, 11 or galea on the tip of the movable between which is a sucker or adhesive pad enabling the I finger. This interesting fact is to be animal to climb smooth and overhanging surfaces. In all compared with the production by species the legs are of two kinds ; the first two pairs are the spider Scytodes (p. 77) of a directed forwards and pull the owner along, the third and mixture of silk and poison which it fourth pairs are stronger, are directed backwards and push spits at its prey. It shows that the the animal along. A false-scorpion runs backwards from FIG. 66.-Chelicerae of poison of spiders' chelicerae i.s homo- . a Chelonethid. . any source of disturbance as quickly as it runs forwards, but logous with the false-scorpions' silk. it does not continue to do so for very long. Like the legs of Thirdly, the chelicerae act as cleaning or preening organs other arachnids, those of false-scorpions are well provided with which the important pedipalpi are continually groomed. with tactile setae. Hence they carry combs or serrulae on both fingers. They It will be seen from this short account that the tiny body also carry sensory setae; and a flagellum, in form character­ of a false-scorpion is as fully elaborated as that of any of its istic of each group of Yamilies, is always attached to the larger relatives and is an excellent object for those who are first segment .. Its function is at present unknown. interested in the use of the microscope. The second pair of appendages, the pedipalpi (Pl. 89}, are the chief weapons of offence and defence, as well as the False-scorpions' habits are not well-known. Their food carriers of a series of twelve tactile setae, the efficiency of is varied and includes the eggs of spiders and insects as well which is maintained by the cleaning actions of the chelicerae. as small animals of many kinds. It is caught and killed by They are large organs of six segments, of which the last two the pedipalpi and transferred to the chelicerae which hold it form a: pincer. Poison-glands with ducts opening at a ter- against the mouth. Liquid nourishment only is taken from I76 I77 M THE SPIDERS AND ALLIED ORDERS BRITISH FALSE-SCORPIONS the prey whose body is emptied by the acti.on of the ~ucking twenty-five or thirty in others, leave the oviduct, but remain -pharynx. Chamberlin has noted that while a Chehfer was attached to the mother's body in a disc-like mass surround­ feeding, its pedipalp was seen to vibrate about a hundred ing the orifice. Here they turn into larvae which retain times a minute and ascribed this to the pulsations of the their positions and are now seen to be arranged in a circle -sucking organ. Occasionally the prey is removed from the round the opening of the oviduct, their heads inwards; The ·mouth and held in one of the pedipalpi, but as a rule the residue of the ovaries within degenerates and produces a pedipalpi are stretched out in an attitude of attention during nutrient fluid-false-scorpions' milk-which the larvae suck the meal. · in. They have a large trunk-like proboscis developed at The use of the silk from the chelicerae for building nests this stage and used only for this purpose. The size of the has been described by Kew. The nests are either wholly of mother's_abdomen now rapidly decreases. silk or of silk with an outer coating of pieces of grit ; they After a time the larvae moult and become nymphs. are roughly circular but their form may be affected by ~he These leave their mother, become independent and forsake situation in which they are made. The false-scorp10n the nest to forage for themselves. begins by collecting small pieces of solid material which are Like other Arachnida, false-scorpions grow by periodic .arranged in a circle. Silk is then brushed ove: them from moultings ; there are three moults after the larval stage. the spinneret in' the chelicera, the animal workmg fro~ the The process of moulting is, however, very different from that inside, crossing and re-crossing innumerable th.reads m all already described for spiders and harvestmen. directions. At first, while the rampart is still low, -the The animal constructs a nest and lines it laboriously with .animal can reach over it and pick up particles lying outside. silk for many days. If then rests, as if dead, its legs and lrl Later it has to climb out and make longer journeys to fetch pedipalpi extended, for ten days or more. The carapace 'I more. The material is picked up by the pedipalpi, trans­ now becomes detached and the animal, swelling visibly, I ferred to the chelicerae and added to the existing structure slowly withdraws its body through the aperture. The legs I until the dome is completed. The nest is never coated with and the large pedipalpi are the last to be extracted, so that :silk outside, but the inside is brushed over and over for some as the new and obviously larger nymph appears, all its limbs -days with layer after layer until a continuous sheet isyro- are bunched together and drawn backwards towards the old -duced. Thus the false-scorpion builds its nest round 1tself exoskeleton. The large forceps of the pedipalpi are pulled ·in a manner which is remarkably similar to the way in out in a soft semi-fluid condition and are flattened and ·which the Eskimo constructs his igloo. shaped by contact with each other. These nests are used for moulting, for hibernation and for At first the newly-moulted adult is almost colourless, with . I protecting the eggs and young. Their development. is limbs of china-white appearance. Soon these parts turn -remarkable. The eggs, three or four in some spec1es, green; later the green changes to brown, and the normal 178 179 THE SPIDERS AND ALLIED ORDERS colour is restored by the time the false-scorpion breaks out of its nest. In its adult life the false-scorpion preserves its reputation for eccentricity by one of the most remarkable courtships ever described. The male meets the female face to face and seizes her chelicerae in his own. He shakes a pedipalp or a foreleg before her in a characteristic way and leads her on a kind of "dance." Then he deposits on the ground a spermatophore which consists of an almost erect rod bearing on the top a drop of the vital fluid. He backs away from this and so leads the female over it that it enters tlte oviduct which with his pedipalpi he holds open to receive it. CLASSIFICATION.-In the system contained in Chamber­ lin's monograph (1931) the twenty-four British species listed below are contained in six families and eight genera. A rather simplified method of separating these is offered here, based in the first instance on the continuous or divided nature of the tergites and on the number of the eyes, since these features are easily observed. The list of British species is. as follows -

CHTHONIIDAE OBISIIDAE Chthonius halberti Obisium muscorum Chthonius ischnochelus (C, Obisium carpenteri rayi) Obisium maritimum . Chthonius orthodactylus Roncus lubricum (Obi- Chthonius tenuis sium sylvaticum) Chthonius tetmchelatus CHELIFERIDAE IDEORONCIDAE Chelifm' latreilli I deoroncus cambridgei · Chelifer cancroides (Ch. CHEIRIDIIDAE hermanni) Cheiridium muscorum Withius subruber ,. ?S3P BRITISH FALSE-SCORPIONS ,,,!' CHERNETIDAE Chernes nodosus Chernes powelli Chernes godfreyi Chernes wideri Chernes chyzeri Chernes panzeri Chernes scorpioides (Ch. Chernes cyrneus phaleratus) Chernes cimicoldes (Cheli- Chernes dubius fer meridianus) The genera may be divided by the following table-

I (8) Tergites without median division (Fig. 68). 2. 2 (5) Two eyes. 3· 3 (4) Chelicerae without galea. Roncus (p. 183). 4 (3) Chelicerae with galea. ldeoroncus (p. 183). 5 (2) Four eyes. 6. 6 (7) First tarsus of one segment. Chthonius (p. r8r). 7 (6) First tarsus of two segments. Obisium (p. r8z) . . 8 (r) Tergites with median division (Fig. 67). g. 9 (ro) No eyes. Chernes (p. 184). ro (9) Two eyes. n. n (12) Eyes placed far back. Cheiridittm (p. 183). I il 12 (n) Eyes near iore-edge of cephalothorax. 13. 13 (14) Articulation between trochantin and femur of legs is wide and oblique. CheUfer (p r85.). '11[, 14 (13) This articulation narrow and vertical. i' 1, Withius (p. 186). CHTHONIIDAE Of the five species of Chthonius in the above list, one, Chthonius halberti, is known only from Ireland, where it was discovered in 1915. The rest are comparatively common. Chthonius ischnoqhelus (Fig. 67), a frequent synonym of :which is Ch. rayi, is one of the m9st abundant, both indoors M rF:r. and out. It is 2·0 mms.long and may be distinguished'from Pl. Sg. PALPI OF FEMALE 181 1 Nemastoma lugubre ( x 10) p. 157. 2, Platybunus triangularis ' ( x 10) p. 170. 3, Chthonius ischnochelus (X 35) p. r8L · THE SPIDERS· AND ALLIED ORDERS BRITISH FALSE-SCORPIONS

I'I its relatives by having the fingers of its pedipalpi much gariff, Cork, in 1909, and known also to be very common irb longer than the bulb (Pl. 89), its cephalothorax mu~h wider Corsica and Algeria. It is 3'3 mms. long. .

in front than behind, and its eyes about two diameters Obisium muscorum is a large reddish species, 2·8 mms .. ,I I·. apart. long, and one of the commonest and most widely distributed 1 ;:,' Chthonius orthodactylus is a smaller species I-5 mms. long, British species. It has been found under stones and among I, ,,, generally recorded from the south-eastern counties of leaves or moss, in the open and in woods from sea-level to· '!'i England, but also to be found on the altitudes of more than 3,000 feet. The forceps of the pedi­ Malvern Hills. It may be distinguished palpi are much longer than the bulb, a character which is from ischnochelus by its cephalothorax, found in carpenteri, but which distinguishes both from the which is only a little wider in front than next species. behind, while its eyes are less than two Obisium maritimum is larger, 3·2 mms. long ; it is found diameters apart. on the seashore-in rock crevices and under embedded Chthonius tenuis is a species confined stones-on the western and south-western coasts, as well as to the south of the Thames. Its distin­ in Ireland. It is a brownish species, and the pedipalpal ,guishing features are the slightly curved forceps are equal in length to the bulb. forceps of the pedipalpi (these being Roncus lubricum differs from the other members of its. straight in the other species), which are family in having two eyes, instead of four, less than one much lighter in colour than the rest of diameter from the fore-edge of the carapace. It is confined FIG. 67.-Dorsal view of Chthonius the limb. to the south and south-west of this country, and has been ischnochelus. Chthonius tetrachelatus is the same size recorded from Ireland. Its length is 2·5 mms. (X II) as orthodactylus, and is much commoner near the sea than farther inland. I have found it abun­ IDEORONCIDAE dantly in Cornwall, and it is widely distributed elsewhere, Ideoroncus cambridgei is a two-eyed species, 2·3 mms.long. both in Britain and Ireland. Its distinction from ortho­ It is apparently well distributed in Ireland. In this country dactylus lies in the pedipalpi, the fingers or forceps of it is confined to the western counties, where it occurs ne::tr which are only a little longer than the bulb ; and in the the coast, sometimes plentifully. more generally dark green colour of the abdomen.

OBISIIDAE CHEIRIDIIDAE This family, like the last, includes one species known only Cheiridium muscorum has two eyes, far removed from the from Ireland. This is Obisium carpenteri, found at Glen­ fore-edge of the cephalothorax. It is only r·r mms. long, r82 T83 THE SPIDERS AND ALLIED ORDERS BRITISH FALSE-SCORPIONS. and is our smallest species, but it is widespread and generally have been used by domestic animals, and in hollow trees abundant in ~my of the situations, indoors or out, where used by.owls, or in birds' nests. It is common and widely false-scorpions may be found. It often occurs in company distributed. It is dull red-brown in colour, with strong with Chernes panzeri. It is a dull-brown colour, with pale smooth pedipalpi. abdominal setae. Chernes cimicoides, 2·5 mms.Iong, is a tree-dweller, found under closely-fitting bark of dead or dying trees and CHERNETIDAE recorded from neady all the forest regions of Britain south Chernes nodosus is a species r-7 mms. long with reddish­ of the Mersey and Humber. It is a dull-brown colour, with brown cephalothorax and greenish abdomen. It is gener­ a broadly swollen bulb on each pedipalp, the surface of ally distributed. in Britain, where it frequents heaps of which is roughened. vegetable refuse and manure heaps in gardens. It is the Chernes cyrneus is a rarer species found in the same situa­ species which most frequently holds on to the legs of flies and tions. It is a dark brown, almost black, species, and is the harvestmen (see p. 149), and is sometimes seen in these largest British false-scorpion, being 3·6 mms. in length. situations in the autumn. Chernes wideri and C. powelli are two closely allied Clternes godfreyi is the same size and also grasps flies. It species, 2·4 mms. long. The former is a tree-dweller and is is much rarer than nodosus. These two species have a rare ; the latter lives in vegetable refuse and is more widely tactile seta on the tarsus of the fourth leg ; near the middle distributed. of the segment in godjreyi, nearer the proximal end in CHELIFERIDAE nodoszts. Chernes scorpioides has similar tactile setae. It is another The two species of Cltelifer are both rubbish-dweller ofthe same size, with a browner abdomen large. Cltelifer latreilli is 2·9 mms. long than nodosus and distinct granulations on the cephalo­ and is confined to the seashore, where thorax. It sometimes occurs in numbers in the nests of the it occurs in sand-hills, among grass-roots red ant, Formica rufa. and in rock-crevices. It is a dark-brown Chernes dubitts is a pale-reddish species, r~6 mms. long. species, characterized by its smooth It generally lives under stones and is usually found near the tarsal claws, and has been recorded from sea, sometimes almost at high-tide mark. Its setae, like many localities all on the south and east those of scorpioides, are club-shaped instead of being simple coast. Chelifer cancroides (Fig. 68) is 3·2 "hairs." FIG. 68.-Dorsal Chernes panzeri is a larger species, 2·6 mms. long. It is mms. long and is green-brown in colour. view of Chelifer often found in buildings such as stables and cowsheds which It lives in buildings only and hence is cancroides. 184 I85 THE SPIDERS AND ALLIED ORDERS probably a:n importation, though long established. It has a single tooth on each tarsal claw. . SHORT BIBLIOGRAPHY OF BRITISH Withius subruber, .5 mms., is an imported spec1es estab­ 2 FALSE-SCORPIONS lished in buildings and in the open in the south ?f England. ,I It has distinctive pedipalpi in which the .bulb 1s e~ongated I. 0. Pickard-Cambridge, 1892. "On the British Species of ~ I and the forceps are shortened in companson. It 1s a red­ False-Scorpions," Proc. Dm'set Field Club, xiii, pp. i99-231. brown colour. H. W. Kew, 19n. "A Synopsis of the False Scorpions of Britain and Ireland," Proc. R. Irish Acad., B. xxix, pp. 38-64. H. W. Kew, 1912. " On the Pairing of Pseudoscorpiones," Proc. Zool. Soc., pp. 376-go. H. W. Kew, 1914. " On the Nests of Pseudoscorpiones," Proc. Zoo!. Soc., pp. 93-III. H. W. Kew, 1916. "A Synopsis of the False Scorpions of Britain and Ireland: Supplement," Proc. R. Irish Acad., B. xxxiii, pp. 71-85.

E. Simon, 1879. Les Arachnides de France, Vol. VII, pp. 1-78, Paris. E. Schenkel, 1928. Die TierweltDeutschlands., VIII, pp. 52-72. J. C. Chamberlin, 1931. "The Arachnid Order Chelonethida." Stanford Univ. Publications. Biological Sciences, VIII, I, pp. 1-284,

./ r86 'I I ''if, I' I ! I !( BRITISH MITES ,!

'1, I' I I Order ACARI I' i THE mites, or Acari, of Great Britain form a vast multitude of small fry, the majority of which are unobtrusive and unfamiliar. Difficulties of collection and of identification and the complexity of their classification make the study of mites a much more exacting business than the study of the other Orders of our Arachnida, and an attempt to treat them here with anything like the. same degree of fullness · would be undesirable. On the other hand, several mites are .familiar and are also of considerable economic importance, so that they may well be chosen as types or representatiVf!'> of this large Order. ' In a recent German work, von Vitzthum has divided the mites into six sub-orders, four of which are represented in Britain. These are the. Parasitifotmes, Trombidiformes, !11, Sarcoptiformes and Tetrapodili. We shall not concern our­ ! ' selves here with the intricacies of their classiftca:tion, but ~~~~ shall be content with short accounts of a few of the com­ 'I, moner species. It will become apparent that many of these I, owe their selection to their unpleasant mariners, which make I, them important pests.

PARASITIFORMES This sub-order includes the family Ixodidae to which the ticks belong. Ixodes ricinus, the castor bean tick, is the common para­ r88 BRITISH MITES site of sheep and cattle in this country. The easiest way to catch them is to take a dog for a walk in a field in which affected sheep have been kept, when some of the ticks are certain to be brought out fixed to the clog's skin. They are unpleasant looking pale oval animals, with a brown head and brown legs. As obtained thus, their characteristic mouth-parts are embedded in the dog and force will only tear them. The tick should be treated with a drop of chloroform or benzene, when it may be more easily removed. 0 01 The eggs of ticks are laid on the ground or in a crevice and H hatch as larvae which possess only six legs. The larvae 0 climb the grass and· wait until an animal passes. At its

X'" approach they exhibit great activity and if possible seize its hair as it passes. When once secure the larva plunges its ro&trum into its host's skin and sucks its blood until gorged. It then detaches itself and drops to the ground, where it hides until its large meal is absorbed and other changes occur. Then it casts its cuticle and becomes a nymph, with eight legs but sexually immature. The nymph climbs the vegetation and repeats the actions of the larva, moulting again after gorging itself to produce a mature male or female. These again seek hosts. Mating takes place on the host's body, and finally the well-fed fertilized female drops to the ground to lay her eggs. Such a life-history is fl!ll of risk, and hundreds of larvae and nymphs perish without finding a host. The common tick, though a serious irritation to sheep, is not acarrier of disease, as are many ticks in hotter countries. Poultry and pigeons are subject to attack from a variety of mites, one of which, Argas rejlexus, is yellow and white in colour and is liable to attack man. 189 THE SPIDERS AND ALLIED ORDERS BRITISH MITES The third universally distributed mite of this group is TROMBIDIFORMES Demodex folliculorum. It lives in the hair follicles and A large number of British mites come within this· sub;. sebaceous glands of man, most frequently on the forehead, order, including at least three very common species. Many nose and chin, and related species or varieties are found in people suffer in autumn from the bites of" harvesters," and dogs, cats, cows, and pigs. Obviously these parasites are these are the larvae of one or more species of Trombidium. very minute and can be seen only under a microscope. The larvae are particularly numerous in late summer and They may be discovered by pressing out the contents of a autumn and will feed on any small mammal, such as a rabbit " blackhead " pustule and examining it in a drop of xylol or a mole. They force their mouth parts into the skin, which dissolves fat. The mite is an elongated form, with a which then hardens round the pharynx in a cylinder, the tapering annulated abdomen and eight tiny legs. The female so-called proboscis. The resulting irritation is of very lays oval eggs, from which a legless larva first emerges. different intensity in different people ; ordinarily there is Another important parasitic mite, the smallest of all the nothing· worse than a rash and no disease is known to be Order, is the well-known Acarapis (Tarsonemus) woodi. This mite lives and breeds in the breathing tracheae of the conveyed by these mites. The very common and familiar red spiders are mites of honey-bee, and is the cause of Isle of Wight disease. The this group, by name Tetranychus telarius and T. bimaculatus mites in small numbers are harmless. Soon, however, their (Pl. 95). These are small mites, but are capable of repro­ attacks disturb control of the wing muscles, so that infected ducing so rapidly that they soon become a serious pest to bees cannot fly, and later, as they multiply, the tracheae are fruit-growers. In glass-houses T. telarius attacks cucum­ choked by their bodies, and the bee dies of suffocation. bers and tomatoes, in the open air hops and strawberries. To this sub-order also belong the water-mites and the They are vegetarians, and by sucking the sap of plants, Bdellidae or snout mites. The latter are not very numer­ injure the leaves and give them a blistered appearance. ous ; to the former belong a large number of species, of Trouble begins in the spring as soon as the weather is warm which about 250 are found in Britain. Some live in salt enough to awaken the sleeping mites, and continues through­ water, but the majority are found in ponds and rivers. out the summer as successive generations feed and lay their They are among the most beautiful of all the mites, having eggs on the leaves. The Tetranychidae are also known as a rich and varied colouring and a great diversity of shape spinning-mites, for they have the power of producing silk (PI. 94). Their legs are provided with long setae, by which from glands which open into the mouth and are probably they can swim rapidly. They are predaceous, and the modified salivary glands. In autumn these mites become young of many are parasites. gregarious and live in a communal web, sometimes so large A good way in which to find some of the commoner mites that masses of vegetation are covered with their silk. of this sub-order is to fill a large tin with fallen leaves, r9o I9I THE SPIDERS AND ALLIED ORDERS BRITISH MITES drifted rubbish, and other vegetable debris, and then in the parous, a fact which saves time in their development, so laboratory to search it piecemeal on a sheet of white paper. that in favourable circumstances they multiply with great All sorts of wild game will occur, and mites are sure to be rapidity and soon completely consume a piece of cheese. included among them. In this ·way I have found Per­ Favourable circumstances are warmth and damp, and in a gamasus crassipes, a red-brown species, in which the fi:st legs dry atmosphere they are unable to survive. As their food of the male are characteristically swollen; Anystzs buc­ is consumed and a change from plenty to famine occurs, the corum a red mite I mm. long; Molgus littoralis, a very oldest and the youngest mites generally die. The rest, small ~pedes ; and a dark species of Erythraeus, with very however, have the power of transforming themselves into a long fourth legs. . . form, known as the hypopus, specially adapted for resistance Other ways in which mites come under notice mvolve and distribution. The hypopus has a hard brown pro­ their habit of achieving dispersal by clinging to the bodies of tective covering, and it does little but await the arrival of other animals. This habit, known as phoresy, has already a fly or some other visitor. It then clings to the hairs on been mentioned in describing the false-scorpions, some of the legs of the insect apd is carried to other surroundings. which take rides on house-flies. Mites belonging to the Sugar mites, Glycyphagus domesticus, and flour-mites, family Uropodidae are often attached to beetles, not as Aleurobiusjarinae, are also common in some parts, attacking parasites, but solely as passengers. The mite is fixed to the stores of food-stuffs of all kinds. beetle by a thread composed of solidified excrement. Many The typical genus of this sub-order is Sarcoptes scabei, the other mites attach themselves to ants, sometimes as true unpleasant parasite known as the itch-mite. These have parasites, and ants' nests are gooci places in whic? to sea:ch flat oval bodies, pearly grey in colour, with short legs ending for mites. Nearly forty species of myrmecophtlous m1tes in hairs or suckers. The female Sarcoptes burrows in the are known in Britain. Again, the crane-fly is often found to , human skin, laying eggs as she goes, until after two or three be the bearer of a mite, Belausthem (Ritteria) nemorum, a months she has excavated a tunnel some centimetres long largish mite whose red larva is dispersed in the autumn in and filled with a hundred or more eggs and many dots of this way. black excreta. From this tunnel she cannot escape, but the eggs soon hatch, and the escaping young rapidly spread SARCOPTIFORMES infection. They may be transferred by contact to other In this group are some familiar soft-bodied domestic persons or to horses, cattle, dogs, and cats. mites, of which the cheese-mites, Tyroglyphus siro and T. longior are the best known. These two species are often TETRAPODILI found feeding together, and they are ableto live on many All naturalists are familiar with the galls found on the other substances besides cheese. These mites are vivi- leaves of trees and other plants. Many of these (though by I92 I93 N THE SPIDERS AND ALLIED ORDERS no means all) are the result of the attacks of gall-mites, •I ., !' belonging to the genus Eriophyes (Pl. 95). Mite-galls can '. 1 be distinguished from galls due to insects since the former BRITISH SEA-SPIDERS have an aperture through which the mite escapes, while Sub-class PYCNOGONIDA insect larvae are usually imprisoned. Mite-galls are gener­ ally covered with a felted mass of" hair," the product of the STRUCTURE AND HABITS.-The Pycnogonida, also known plant cells stimulated to abnormal growth, and in the middle as Pantopoda, Podosomata, Sea-spiders or Nobody-crabs of this dense mass the mite is often difficult to detect. As are a class. of marine Arthropoda whose exact relations hav~ examples of common mite-galls the red growths seen on long been a matter of discussion. They were at first sycamore leaves may be mentioned. The "witches' thought to be allied to the Crustacea, but as their structure brooms " or bundles of small twigs so often seen on the has be7~ more carefully scrutinized and more fully known birch and other trees are due to the attacks of mites, as are the opmwn that they more closely allied to the Arachnida the round red galls on alder and t~e " nail-galls " on lime has become more and more firmly established. Indeed the trees. Mite-galls may also be found on lichens. latest authorities suggest that the Class Arachnomo;pha However, the most familiar mites of this group are the should be regarded . as containing three sub-classes, the common pests of fruit-growers, Eriophyes ribis, the cause of Merostomata to include Limulus, the Pantopoda to include big-bud in black-currants and E. pyri, which is the pear leaf the sea~spiders,. and th: Arachnoidea, for the land-living blister mite. Both these mites are capable of attacking ~rach~1cla. It Is on tlus proposal that the justification for other plants than their usual ones, and are well able to ruin mcluclmg sea-spielers in this book is based. · a crop. The remarkable appearance of a Pycnogonicl is due to the The presence of E. ribis on a currant bush causes the ~xtrem~ reduction of the body, so that the animal gives the infected buds to swell to about double their normal size and Impres.swn of consisting of a bunch of legs. These, with the to die early in the summer. The mites now leave the bud ?ther limbs, are attached to the prosoma, while the abdomen and move to the leaves, and on bright days when a slight IS reduced to a tiny unsegmented sac between the fourth breeze is blowing they migrate. To do this they either cling coxae. Hence all the essential organs are crowded into the to the legs of passing insects, or they spring upwards and are cephalothorax and overflow, as it were, into the legs. carried by the wind through the air. At the height of Offshoots from the gut and reproductive organs pass into migration, many hundreds of mites leave a bud in a day, the femora and even beyond, so that eggs may be seen and little bunches of mites may be seen rolling out of buds developing inside the limbs. · on to the leaves below. The :ephal~thorax is outwardly unlike that of any other arachmd, for 1ts narrow median part is produced into four 194 195 I THE SPIDERS AND ALLIED ORDERS lateral processes which support the legs. In front it carries a proboscis, a tubular organ which is quite short in some species and in others as long as or longer than the rest of the body. At its tip is a triangular opening, the mouth. This organ may not seem to be one which suggests the arachnid character of these animals, but it is an example of the fact · that almost every seeming peculiarity of the Pycnogonid can be matched somewhere else among the Arachnida. In this instance a tubular proboscis is found in the Palpigradi. The foremost segment of the cephalothorax also carries three pairs of appendages, some or all of which may, how­ ever, be absent in certain groups. These appendages are the chelophores, the pedipalpi and the ovigers. The chelophores, also called the chelicerae or mandibles, are two- or three-segmented limbs, very variable in size and shape. They are, however, always pincer-like; the last segment works against a prolongation of the one before it, as in the large, familiar weapons of scorpions and lobsters. The pedipalpi, as in all ordinary Arachnida, are tactile organs. They are composed of five to ten segments and the last few segments, at least, carry setae as do the tactile palpi of spiders, harvestrnen and others. The ovigers, sometimes called ovigerous legs or false legs, are usually more fully developed in the male than in the female, in which sex they are sometimes absent. They arise ventrally in front of the first pair of legs and consist of five to ten segments, the terminal ones carrying specialized spines which help in the function of carrying the egg-masses. The legs have eight segments, named coxa i, ii and iii, Pl. 92. N I

TANYSTYLIDAE Clotenia orbiculare belongs to a genus which differs from Ammothea in that the pedipalpi consist of five or six seg­ ments only. It is a very small species, I mm. long, and has so far been recorded only from the Donegal coast.

PYCNOGONIDAE

FIG. 6g.~Chilophoxus spinosus. The only British member of this aberrant family is also the commonest of our sea-spiders. Chilophoxus spinoszts (Fig. 69) is 3 to 6 mms. long and is Py'cnogonum littorale (Fig. 70) is a· robust species with usually dull green in colour, often with red marks. It is short stout legs with one claw. It is 15 to r8 mms. long, very common among algae and hydroids between the tide- pale yellow to brown in colour and characteristically covered 202 203 THE SPIDERS AND ALLIED ORDERS with small knobs or tubercles. It has the wide range shared by Chilophoxus and Phoxichilidium ; in Britain it is some­ times found inshore, but more generally it is dredged from

FIG. 70.-Pycnogonum littorale. depths down to 500 fathoms. Ocasionally a trawl l1as brought up a crowd of several thousands of individuals, all taken together. It has been said to attack and eat sea­ anemones This short description of the British sea-spiders should serve as an introduction to a neglected group which would well repay further study. The best general account in English is W; d'Arcy Thompson's contribution to the Cam­ bridge Natural History. It is, however, 35 years old and should be supplemented by H. Heifer's chapter in Kukenthal und Krumbach's Handbtfch der Zoologie, Vol. Ill. E. L. Bouvier's section in Faune de France, VIII, is quite indis­ pensable, and the serious student will find in H. Heifer and E. Schlottke's "Pantopoda" in Bronn's Klassen ·und Ordnungen aes Tierreichs, an admirable treatise which surveys nearly all extant research. 204 THE SPIDERS AND ALLIED ORDERS

BLACKWALL, 1861 PICKARD-CAMBRIDGE, BRISTOWE, 19J9 1900 GLOSSARY Epeira scalaris Epeira pyramidata Aranea raji - quadrata - quad1'ata - 1'eaumuri Abdomen-the hinder portion of a spider's body, properly called the - umbratica - umbratica - sexpunctata - cornuta - foliata opisthosoma. - apoclisa Apophysis-a projecting outgrowth or process. - bicornis - gibbosa - gibbosa Calamistrum-the comb of short spines on the metatarsi of the fourth ·- bella Cercidia prominens Cercidia prominens legs of certain spiders. Cephalothorax-the fore-part of a spider, the head and thorax together, properly called the prosoma. Chelate-pincer-like, as the claw of a lobster. Chelicerae-the " jaws " of an arachnid, carrying the poison fang in the spiders. Chitin-a complex nitrogen compound of which the hard parts of many invertebrates are made. Clypeus-the narrow strip of cephalothorax between the eyes and the bases of the chelicerae. Colulus-a small conical appendage between the infefior spinnerets. Coxa-the first segment of an arachnid's leg or palp, attaching it to the body. CribeUum-a sieve-like plate in front of the spinnerets of certain spiders. Direct eyes-the two middle eyes of the front row. Distal-the end of a limb or segment farthest from the body. Diverticulum-a blindly ending, branched passage. Ecdysis-casting the outer skin in growth; "moulting:' Epigastric furrow-the transverse groove behind the reproductive region of the abdomyn. Epigyne-the external genitalia of the female arachnid . . Exoskeleton-the protecting and supporting structur(Js, usually of chitin, outside tl).e body. Family-a group of related genera. Femur-the third segment of an arachnid's leg or palp. Fovea-a groove or furrow. Genus-a group of related species. Gnathobase-a projection from the coxa of a limb used to crush food. Labium-the lower" lip " or lower surface of the mouth, between the maxillae. Latet·igrade-:arranged to run sideways. 215 THE SPIDERS AND ALLIED ORDERS

Mandible-the chelicerae or falces. M axillae-.the inner swellings on the coxae of the palpi, used to masticate the food. GENERAL INDEX Metatarsus-the penultimate segment of an arachnid's leg. Ocelli-eyes of simple form, with smooth surfaces. Palp, Palpus (pi. palpi)-the leg-like tactile organ in front of the Aranea raji! I32· PI. 78 Acarapis woodi, I9I - reaumun, I32. Pis. 78, 86 spider's legs, bearing the maxillae and the male organs. ACARI, I88 - sexpunctata, I32· Pis. 78, 87 Patella-the short leg segment, between the femur and tibia. Agelena, 85 -labyrinthica, 86. Pis. 27, 33, Arctosa, 95 Pectinate-having teeth like a comb. - perita, 95· PI. 4I Pedicle-the narrow " waist " of a spider, uniting the cephalothorax 34 AGELENIDAE, 42, 84 Argas reflexus, I89 and abdomen. Agroeca, 67 Argenna, 82 Pedipalp-a more exact term for the palpus. - bnmnea, 71. PI. 25 - subnigra, 82 Phylum-the biggest division in classifying the animal kingdom. Argyope aurantica, I34 - proxima, 72 43, I22 Aleurobius jarinae, I93 ARGYOPIDAE, Procurved-curved with the convexity backwards. ARGYOPINAE, I34 Proximal-the end of a limb or segment nearest to the body. Amaurobius, 85 Argyroneta aquatica, 52. Pis. - atropos, 86. Pis. 33· 34 Recurved-curved with the convexity forwards. I4, I6 Scapula-a brush of " hairs " or setae at the end of a tarsus. - terrestris, 87 ARGYRONETIDAE, 42, 52 Ammothea, I98 Serrula-a row of chitinous teeth, as on the maxillae. - echinata, Ig8, 203 . Asagena, g8, 99 Seta-a hair-like sensory organ on an arachnid's body and lim]?s. - phalerata, IOO. PI. 53 -laevis, Ig8, 203 ASCORHYNCOMORPHA, Ig8 Spines-the stoutest setae. - longipes, Ig8, 203 Spiracle-a respiratory aperture, the orifice of a tracheal tube. -simplex, 198, 203 Attus pubescens, 76 AMMOTHEIDAE, rg8, Igg, ATYPIDAE, 40,45 Sternite-a chitinous plate on the ventral side of a body-segment. Atypus affinis, 45· PI. I1 Sternum___.:.the lower surface of the prosoma, between the coxae of 200, 203 the legs. A nelasmocephalus, I 53 - cambridgei, I53· 156 Ballus depressus, 77 last segment of an arachnid~s leg or palp. Tarsus-the Anoplodactylus, rg8, 20I Bathyphantes, Io8 Tergite-a chitinous plate on the dorsal side of a body-segment. Ig8, 202 - concolor, I09 - angulatus, - dorsalis, Iog. PI. 59 Tibia-the middle segment of an arachnid's leg or palp. - petiolatus, Ig8, 20I Trachea-a tube carrying air into the body. - nigrinus, I09. PI. 62 - pygmaeus, 2oi BDELLIDAE, I9I. PI. 94 Trichobothrium-a very fine seta believed to respond to sound waves - vil'escens, Ig8, 202 Belaustium·nemorum, 148, 192 and so to have an auditory function. A ntistea elegans, 51. PI. IS Anyphaena accentuata, 54· PI. Trochanter-the second, ring-like segment of an arachnid's leg, or Calamistrum, 30. PI. 2 palp. I6 ANYPHAENIDAE, 41, 54 Cannibalism, 32 Unchelate-not pincer-like, having only one blade or point. Anystis buccorum, I92 Cephalothorax, 27 ARANEINAE, I23 Ceratinella, I o6 - brevipes, Io6 ARANEAE, 45 Aranea, I23, 128, 130 -brevis, ro6 - cucurbitina, I3I. PI. 69 - scabrosa, 107 - diadema, I3o. Pis. I, 12, 13, Cercidia, I23, 128 - prominens, 133 v'~fttUr 6~ 65. 73· 75· 82, 84 Chaetonymphon hirtum, rg8, 200 '·.'i';/ q -- foliata, I33· PI.. 78 Cheracanthium, 66 j.! -- gibbosa, I33 217 GENERAL INDEX GENERAL INDEX

Clzeiracanthium erraticum, 6S Ciniflo similis, 84. Pis. 31, 33 Dictyna uncinata, S2 E1·iophyes pyri, 194 CHEIRIDIIDAE, ISo, IS3 CINIFLONIDAE, 40, S3 - viridissima, Sz - ribis, 194 Cheiridium, rSI Classification .of Arachnida, 36 DICTYNIDAE, 41, SI - silvicola, 194· PI. 95 - muscorum, rSo, 1S3 - false-scorpwns, rSo Dicymbium, II5 Era, 8o Chelicerae of false-scorpions, I76 - harvestmen, I 52 - nigrum; n6 - cambridgei, So - harvestmen, 139 -sea-spiders, IgS Diplocephalus, 120 - furcata, 8o -sea-spiders, 196 - spiders, 36 - cristatus, 120 - thoracica, So. PI. 30 - spiders, 27 Clavus, 31 Dipoena, gS, IOI - tuberculata, 8o Chelifer, ISI Claws, 3S. PI. 6 Dolomedes ftmbriattes, gr. P. 38 Erythraeus, 192 - cancroides, ISo, 1S5. PI. 6S Clotenia, IgS Drapetisca socialis, II5 Eugnatha, I23 - hermanni,. rSo - orbiculare, r\)S, 203 DRASSIDAE, 41, 56, 63 Euophrys, 75 -latreilli, rSo, IS5 Clubiona. 66 Drassodes, 64 - erratica, 76 - meridianus, rSI - brevipes, 6g. PI. 20 - cupreus, 65 -frontalis, 75· PI. 30 CHELIFERIDAE, ISo, 1S5 - compta, 6g - dalmatensis, 65 Euryopis, gS, 101. CHELONJ;<:THI, I74 - corticalis, 6g. PI. 20 - lapidicola, 65 Evarcha blancard1, 76. Pis. 28, Chelophores, 196 - diversa, 6g - lapidicolens, 65 30 Chernes, ISI - holosericea, 6g, 70. PI. 23 - lapidosus, 64. PI. 25 Eyes, 27. 37 - cimicoides, 1SI, 1S5 - lutescens, 69, 70 -minor, 65 - chyzeri, ISI - pallidula, 70 - pubescens, 65 False-scorpions, 174 - cyrne1es, ISI, 1S5 - phragmitis, 6g, 70 False-scorpions, list of: 180 . - signifer, 65 Families of false-scorpions, 1So - dttbius, rSI, 1S4 - reclusa, 6g, 70 - silvestris, 6 5 - godft·eyi, ISI, IS4 - subtilis, 6g. PI. 25 Drassus, 64 - harvestmen, 152 - nodosus, I4S·, ISI, rS4 - terrestris, 69. Pls. 23, 26 Dysdera, 4S -sea-spiders, 198 - panzeri, ISr, rS4 CLUBIONIDAE, 41, 56, 66 - crocota, 49 - spiders, 40 . rSr Food of false-scorpwns, 177 - phaleratus, Cocoons, 35 - erythrina, 49· PI. I I - powelli, rSr, rSs Collection, 2 2 DYSDERIDAE, 40, 48 - harvestmen, 146 - scorpioides, rSI, IS4 Corinna, 66 - sea-spiders, 197 - wideri, ISI, rSs - praestans, 6S Eggs, 32, 151, 17S, 197 - spiders, 32 CHERNETIDAE, rSI, IS4 Cribellum, 29 Enidia bituberculata, II9 Formica rufa, 184 CHILOPHOXIDAE, rgS, rgg, Crochet, 3I Enoplognatha, gS, 99 202 Cnestulina, 9S - thoracica, roo Glycyphagus domesticus, 193 Chilophoxus, IgS - guttata, 99 Entelecara, u6, uS Gnaphosa, 63, 65 - spinosus, rgS, 202 Cryphoeca, Ss. 8g -acuminata, uS GNAPHOSIDAE, 63 CHTHONIIDAE, ISo, rSr - silvicola, Sg Epeira, 130 GONATINAE, 105, II5 Chthonius, ISI CTENIDAE, 41, 55 Epigyne, 30 Gonatium, u6, uS - halberti, rSo, rSr Cyclosa, I23, 12S Episinus, gS, IOI - rubens, irS. Pis. 6I, - isclmochelus, I So, IS I. PI. Sg - conica, 128. PI. 69 - truncatus, 104. PI. 53· 79 - orthodactylus, I So, rS2 ERESIDAE, 41, 83 .. - rubeUmn, II9 - rayi, ISO, ISI Demodex caninus. PI. 95 Eresus cinnabarinus, S3 Gongylidium, us. u6 - tenuis, ISo, 182 - folliculorum, 191 - niger, S3 - ruftpes, u6. PI. 76 - tetrachelatus, ISo, 1S2 Diaea, 57 Erigone, 120 Gossamer, 32 Cicurina, 85, Sg - dorsata, 57· PI. 22 - dentipalpis, 120. PI. 81 Growth, 33 - cicurea, go Diblemma donisthorpei, 51 - longipalpis, 120 Ciniflo, S4 Dictyna, SI - promiscua, 120. PI. S3 Halmia candida, 52 - fenestralis, 84. PI. 31 - arundinacea, 8z ERIGONINAE, 105, ug - helveola, 52 - ferox, S4. PI. 36 -latens, Bz E1•iophyes, I94 - rnontana, 51. PI. rS 218 219 GENERAL INDEX GENERAL INDEX

Halmia nava, 52 Leptypltantes pinicola, no, ur. Megabunus insignis, 153, 170 Neriene bituberculata, II9 HAHNIIDAE, 42, 51 PI. 67 Meioneta, 108,- II4 Nesticus, 123, 127 Harpactea hombergi, 4S. Pls. rr, - tenuis, 110, 112 - rurestris, 114 - cellulanus, 127 15 - zimmermanni, uo, rr2. PI._ Nobodycc.rabs, 195 Harvestmen, 136 Melanophora, 65 70 Meta, 123 NYMPHOMORPHA, 19S Harvestmen, list of, 153 Life History of Spiders, 32 - bourneti, 127 Nymphon, 19S, 200 Hasarius adansoni, n, 13-1 Linyphia, 108, rr2 - menardi, 127 - brevirostre, 198, 200 Heliophanus, 75 - clatlwata, II3 - merianae, 126 -gracile, 198, 200 - cupt·eus, 75 - hortensis, II3 - reticulata, 126, Pls. 6S, 69, - grossipes, 198, 200 - flavipes, 75 - insignis, rr4 71, 91 · - megalops, 198, 200 Homalenotus, 139 - montana, II2. Pis. 52, 55, Methods of study, 25 - rubrum, 198, 200 - quadridentatus, 153, 161 57, 6r, 72 METINAE, 123, 126 - stromi, 198, 200 · Hypomma, rr6, II9 - peltata, 114 Micaria, 66 NYMPHONIDAE, 19S, 199, -:- bituberculata, rr9. Pls. sS, - pusilla, rr 3 - alpina, 6S 200 SJ - resupina, II3 - pulicaria, 67 - cornuta, rr9 LINYPHIIDAE, 43, 104. PI. - scintillans, 67 OBISIIDAE, rSo, 1S2 Hyptiotes paradoxus, S1 52 l'vficrommata viridissima, 54· Obisium, rSr LINYPHIINAE, ros, 107. PI. Pls. r6, 17, 1S - carpe.nteri, 180, rS2 IDEORONCIDAE, 1So, 1S3 57 Microneta, 108, rr4 - marit·imtem, 1So, rS3 Ideoroncus, 1S1 LIOBUNINAE, 139, 153, 162 - viaria, II4 .. PI. 72 - muscorum, 180, rS3 t - cambridgei, 1So, 1S3 Liobtmum, 142, 143, 144, 162 MIMETIDAE, 42, 79 - sylvaticum, 1So Introduction, 17 - blackwalli, 153, 163 Misumena, 57, 6o Odiellus, J42, 164 Ischnothyreus velo:>:, 51 - rotundum, 153, 162 - calycina, 6o. PI. 22 - meadi, 153, r67 Ixodes ricinus, rSS Liocranum, 67 Mites, rSS - palpinalis, 153, !67 IXODIDAE, rSS - rupicola, 71 Mitopus, f42, 143, q6, 164 - spinosus, 144· rsr, !53, !67 Lithyphantes, 9S, 99 ..-- alpinus, 165 Oedothora:>:, II5 Labium, 29 LOPHOCARENINAE, 105, 1o6 - cinerascens, 165 - apicatus, u6. PI. 74 Labulla, roS Loplwcarenum parallelum, 107 -moria, 164, 165 - juscus, II6. PI. 74 - thoracica, 1oS. PI. 58 Lungs of spiders, 29 Molgus littoralis, 192 - retusus, u6. PI. 74 Lacinius, 153, 164, r6S Lycosa, 92 Monocephalus juscipes, 12I. PI. OLIGOLOPHINAE, 137, 139, - ephippiatus, 153, 168 - agricola, 93 S3 . 141, 153, r63, r6S Laseola, 9S, ror - herbigrada, 93 Moulting of false-scorpions, 179 Oligolophus, 142, r64 Lathys, S2 - lugubris, 93, 146 - harvestmen, 149 - agrestis, 15!, !53, 165 Legs of false-scorpions, 277 - nigriceps, 93· PI. 46 - spiders, 33 - alpinus, 153 - harvestmen, 159 - pullata, 93· PI. 46 Mouth, 29 - cinerascens, 153 - sea-spiders, 196 - purbeckensis, 93 - hanseni, 153, 166 - spiders, 29. Pls. 3, 4, 5, 6 - saccata, 92. Pls. 41, 46 Nelima, 143 - tridens, 153, r66 Leptyphantes, 1oS - tarsalis, 93· PI. 46 - aurantica, 143 - vittiger, 153 - alacris, rro. PI. 64 LYCOSIDAE, 42, 56, 91. PI. 43 - silvatica, 153, 163 OONOPIDAE, 40, 49 - cristatus, IIO, III. PI. 70 Nemastoma, 140, 157 Oonops domestic-us, 50 -.ffavipes, IIO, III. PI. 67 J\llangora, 123, 12S - bimaculatum, 153 - pulcher, 49 - leprosus, rro. PI. 64 AIaso sundevalli, 105. PI. 56 - chrysomelas, 141, 143, 153, Opilio, 170 - minutus, rro. PI. 56 MASONINAE, 105 158 - albescens, 147 - nebulosus, rro. Pls. 5S, 64 Maxillae, 29 - hegubre, 153, 157 - parietinus, f42, 153, 172 - obscunts, rro, rrr. PI. 67 Megabunus; 143, 169 NENIAS'l'OMA TJDAE, 137, - saxatile, 172 -pallidus, rro, rrr. PI. 67 - diadema, 142, 153, 170 139, 152, 153, 156 OPILIONES, 136 220 22I GENERAL INDEX GENERAL INDEX Salticus cingulatus, 75 Orb-web, 122 Pholctts phalangioides, 78. Pl. Tegenaria, 85 33 - scenicus, 74· Pls. 19, 26, 30 - atrica, 87. Pis. 27, 39, 42 Oviduct, 30 Sarcoptes scabei, 193 Ovigers, rg6 PHOXICHILIDIIDAE, 198, - domestica, 87. Pls. 38, 39 rgg, 2oo, 201 SARCOPTT.FORMES, !'92 -larva, 8g Oxyopes heterophthalmus, g6 Savignia, II5 : OXYOPIDAE, 42, 96 Phoxichilidium je11loratum, rg8, - parietina, 88. Pl. 42 202 - jrontata, I17. PI. 61 - silvestris, 88. Pls. 38, 44 Oxyptila, 57, 59 Scape, 30 Tetragnatha, 123 - atomaria, 59 Phrurolithus, 67 --,- festivus, 70 Sclerosoma Romanum, 161 - extensa, 125. PI. 66 - praticola, 59 SCLEROSOMATINAE 139, - montana, 125. PI. 66 - trux, 59 -- mini·mus, 71 Physocyclus simoni, 79 153, 160 ' - nigrita, 126 Pirata, 92 Scopula, 73 - obtttsa, 126 Pachygnatha, 123 Scotina, 67, 71 - clercki, 124-. Pis. 66, 85 - hygrophila, 94 - pinicola, 126 ,.- latitans, 94 Scotophaeus, 64 TETRAGNATHINAE, 123, - degeeri, 124. Pls. 66, 85 - blackwalli, 64. Pis. 20, 25 - listeri, 124 - piratica, 94· Pis. 41, 45 .124 - umbraticola, 94 Scytodes thoracica, 77 TETRANYCHIDAE 190 Pallene, 198, 201 Sea-spiders, 195 . - brevirostris, 198, 201 Pisaura liste1·i, go. Pls. 29, 32, Tetranychus, 190. Pl.' 95 35· 37· 38. 40, 44 Sea-spiders, list of, 198 - bimaculatus, 190 - producta, 198, 201 Segestria, 47 - spectrum, 198, 201 PISA URIDAE, 42, go - telarius, 190 Pistius, 57• 59 - bavarica, 48 TETRAPODILI, 193 - tiberi, 198, 201 - florentina, 48 PALLENIDAE, 198, 199, 200, Platybunus, qr, q6, 169 Tetrilus, 85, 8g - corniger, 153, 171 · - senoculata, 47· PI. II - arietinus, go 201 SEGESTRIIDAE, 40, 47 - impudicus, go Pantopoda, 195 -triangularis, 142, 153, 170. Pl. Sg S~CARIIDAE, 40, 77 Teutana; 98 PARASITIFORMES, r88 Stnga, 123, 128 Pedipalpi of false-scorpions, 176. Pocadicnemis, n6, uS Textrix, 85 Sitticus pubescens, 76 - denticulata, 85. Pl. 36 PL 89 - pumila, n8. PI. 79 Podosomata, 195 SPARASSIDAE, 41, 54 Thanatus, 57, 61 - harvestmen, 139 Spider, dorsal surface of, 27 Theonoe, 98 - sea-spiders, 196 Preservation, 24 Propodus, rg6. -structure of, 27 - minutissima, g8 -spiders, 21, 29 - ventral surface .of, 29 Pergamastts crassipes, 192 Prosthesima, 65 THERIDIIDAE, 43, g6 -.vertical section of, 33 Theridion, 98, 101 Phaeocedus, 64, 65 Protadia, 82 - patula, 83 Spmnerets, 29. Pls. g, ro. - bimaculatmn, 103. PI. 50 - braccatus, 66 Stearodea, 98 PHALANGIIDAE, 152, 153, Pseudopallene circularis, 198, 201 - denticulatum, 102. PI. 53 PSEUDOSCORPIONES; 174.· - bipunctata, 99· Pis. 51, 53 - lunatum, 103 159 PYCNOGONIDA, 195, 199, 203 Stemonyphantes, 114 - notatum, 102. PI. 50 PHALANGIINAE, 139, 153, -lineata, IJ4. Pls. s8, 72 r6g PYCNOGONOMORPHA, rg8 - pal~en~, 103, Pls. 47, 56 Pycnogonum, rg8 Sternum, 29 - redtmttum, ror. Pls. 49, so, Phalangium; 143, 170 Structure and Habits, 27, 136, - opiiio, 142, 153, 171. Pl. 93 - littorale, rg8, 203 51 174. 195 - t~pidariorum, 103, 134 - saxatile, 153 Ritteria nemorum, 148 - tmctum, 102 Philodromus, 57, 6r T ANYSTYLIDAE, 198, 199, - varians, 102. PI. 5 - aureolus, 6r Roberttts, g8, 99 4 - lividus, 99 200, 203 Theridiosoma, 123 - cespiticolis, 6 r Tarentula, 92, 95 - gemmosum, ·123 - dispar, 61 Roncus, rSr - lubricttm, r8o, 183 - accenfttata, 96 T,HERIDIOSOMATINAE, 123 - jallax, 62 - carinata, 95· PI. 48 1HOMISIDAE 41 56 PHOLCIDAE, 42, 78 SALTICIDAE, 41, 72 - fabrilis, g6 Thomisus, 57, s9 ' Pholcomma, gS Tarsonemus woodi, 191 Tibellus, 57, 61 -gibbum, g8 Salticus, 74• 75 222 223 GENERAL INDEX

Tibellus oblongus, 63 Webs, 122 - parallelus, 62. Pl..22 Wideria, 115 Ticks, 19, 189 - antica, I 17 Tiso vagans, 121 Withius, 181 Triaeris stenapsis:, ·51 - subruber, r8o, .\86 Trochosa, 92, 95 - ruricola, 95 - terricola, 95· PI. 41 Xysticus, 57 TROGULIDAE, 137, 139, qr, - auda:>:, 58 152, 153 - bifasciaflts, 58 Trogulus, 153 - kochi, 58 - rostratus, 153 - robustus, 59 - tricarinatus, 153, 155 ~ sabulosus, 58 TROMBIDIFORMES, 190 - viaticus, 58. PI. 22 Trombidium, 190 Troxochrus cirrijrons, 121 - scabriculus, 122.. PI. 83 Zelotes, 63, 65 Tuberta, 85, 89 - apricorum, 66 - moerens, go - ater, 66 Tyroglyphus longior, 192 - petiverii, 66 - siro, 192 Zilla, 123 Zora, 55 ULOBORIDAE, 41, 81 - arrnillata, 56 Uloborus, 8r - nemoralis, 56 - walckenaerius, 81 - spinimana, 55· Pis. r6, 20 UROPODIDAE, 192 Zygiella, 128 - atrica, 129. PI. 87 Walckenaera, II 5 - litterata, 130. Pis. 6g, 87 -acuminata, II7. PI. 6r - stromi, 129. Pis. 88, go

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