BULLETIN DE L'INSTITUT ROYAL DES SCIENCES NATURELLES DE BELGIQUE, ENTOMOLOGIE, 65: 63-71, 1995 BULLETIN VAN HET KONINKLIJK BELGISCH INSnfUUT VOOR NATUURWETENSCHAPPEN, ENTOMOLOGIE, 65: 63-71, 1995 10, 7 2

A new phoretic deuteronymph of Halodarcia KARG (: : ) associated with carabid beetles In Belgium with a review of the genus.

Gwilym O. EVANS and A. FAIN

Abstract Description of species Order Mesostigmata The deuteronymph ofHalodal'cia cal'abidophila sp.nov. occurr­ Family Halolaelapidae KARG ing under the elytra of four species of Carabidae (Insecta) in Genus Halodarcia KARG 1969 Belgium is described and compared morphologically with the same instar ofthe two previously described species ofthe genus, Deuteronymphs with podonotal and opisthonotal shields, Halodal'cia incideta KARG and Halodal'cia pOl'olata KARG. The adults with holodorsal shield; podonotal shield of deuteronymphs ofH. incideta and H. pOl'olata are shown to have deuteronymph with 15 or 16 pairs of setae, zl on been assigned originally to the wrong species resulting in the unsclerotized cuticle, opisthonotal shield with 10-13 pairs; deuteronymph of H. incideta sensu KARG 1969 being transfer­ red to H. pOl'olata and that of H. pOl'olata sensu KARG 1969 podonotal region of holodorsal shield of female with 16 to H. in cideta. A key is provided for the identification of the or 17 pairs of setae (zl on shield, s4 on shield or on deuteronymphs. The relationship of the genus Halodal'cia to unsclerotized cuticle), opisthonotal region with setae J3 other genera included in the Halolaelapidae is discussed and a absent, J5 in advance of Z5 and with 4 pairs of 8 setae division of the family into two subfamilies, Halodarciinae and (85 offshield). Podonotal and opisthonotal regions each Halolaelapinae, is proposed. with 4 pairs of primary gland pores (gd7 present), large K,ey words: (Acari: Halolaelapidae). Sub-elytral phoretics in adult's, supernumerary gland pores on podonotum pre­ of Carabidae (Coleoptera). Belgium. sent or absent; gland pores gd3 and 10 associated with peritrematic shield. Posterior region ofidiosoma ofadults with aciculate areas resembling cribrum of ventrianal shield. Sternal pores iv3 lacking; gv3 duplex, solenostomes on platelet. Presternal shields' strongly developed in the female; sternal shield fused with endopodal elements of Introduction coxae l-I1 and I1-III in adults but not in deuteronymph; genital shield of female with hyaline flap produced into The mites forming the subject of this work were found slender pointed process; adults with ventrianal shield, under the elytra of four species of beetles of the family deuteronymphs with anal shield; peritrematic shield Carabidae in Belgium. All are deuteronymphs and enlarged in the adult and free or fused with the exopodal members of the genus Halodarcia KARG shield of coxa IV. Spermatodactyl directed anteriorly and (Halolaelapidae). They were collected by Dr. M. hook-like at extremity. Seven transverse rQws ofdenticles DUFRENE and Mr M.1. NOTI, Department of Ecology on subcapitulum (Q2-Q8), Qx row weakly developed; and Biogeography, Catholic University of Louvain, rows not confined to capitular groove in adults. Pedipalp Belgium in the course of ecological studies on the apotele three-tined, chaetotaxy ofpalptrochanter to genu Carabidae of Belgium. A list of mites collected from (2-5-6). Genu and tibia of leg I each with 6 dorsal setae carabid beetles in Belgium, including a redescription of (2-312-3/1-2), femur I with 13 setae, genu III with 9 setae. the deuteronymph of Halodarcia incideta KARG 1969, has Leg II ofmale without spurs. Sensory field of tarsus I in been published by FAIN et al. (1995). They referred to the nymphs and adults with conspicuous goose-neck sensillus; new species described in that work as Halodarcia sp. acuminate paradactyli and setae adl-pdl oftarsi I1-IV of The terminologies for the dorsal idiosomatic chaetotaxy protonymphs and adults extending well beyond the and the leg chaetotaxy follow the systems of LINDQUIST ambulacrum. Adults free-living in litter and humus in & EVANS (1965) and EVANS (1963), respectively. The damp or wet situations; deuteronymphs, ofat least some system of nomenclature for the cuticular glands and species, sub-elytral phoretics of carabid beetles. "poroids" is that of Athias-Henriot (1971, 1975). Type species: Halodarcia incideta KARG 1969. 64 G.O. EVANS & A. FAIN

Halodarcia carabidophila sp. novo of three sigilla and on an antero-ventral projection (Fig. 6). All dorsal and ventral shields micropunctate. Deuteronymph: Dorsum of idiosoma with two shields, Cheliceral digits relatively shorter and stouter than in podonotal shield 250-275 flm in median length and Halodarcia porolata and H. incideta (Fig. 16), fixed digit 190-240 flm in width at the level ofsetae s3, opisthonotal with five teeth, the three proximal teeth considerably shield 200-220 flm in median length and 208-225 flm at stronger than the two distal; pilus dentilis as in Fig. 7. anterior margin (Fig. 1). Podonotal shield with fifteen Movable digit (46 flm in length) with four or five small pairs of setae comprisingj1-j6,z2-z6 and s2,s3,s5,s6. Setae teeth; antiaxial and dorsal slit organs present, dorsal seta zl short (12-15 flm), subspinose and situated on unscle­ well developed. rotized cuticle anterior to the shield. Setae of the Gnathotectum subtriangular in shape with toothed lateral podonotal shield smooth and subequal :j1 (19-23 flm),j5 margins and tapering bifurcate median process (Fig. 8). (24-25 flm), z5 (26-28 flm). Surface of shield reticulate, Subcapitular groove with seven transverse lines (Q2-Q8) with four pairs of gland pores (gll,2,4,5 - open circles in with few or several denticles, line Qx inconspicuous and Fig. 1) and five pairs of poroids (represented in solid without distinct denticles; hypostomatic and palpcoxal black). Sigilla indicated by dotted areas. Seven pairs of setae subequal in length (Fig. 9). Palpomeres with nor­ setae on lateral unsclerotized cuticle. mal complement of setae; seta v2 on trochanter pilose, Opisthonotal shield normally with ten pairs of setae al on femur and all and al2 on genu pilose and spatulate (10-10) comprising JI,2,4,5; zl-5 and S2 (Fig. 1), variants in distal half; palpal claw (apotele) with three prongs, with 9 setae on one side due to the absence of Z3 or Z4, posterior prong slender. or with 11 setae on one side of the body resulting from All legs with ambulacra comprising lobed pulvilli and the addition ofS3 (Fig. 2), S4 or 13 (Fig. 3). Setae simple paired claws. or sparsely barbed, subequal in length, J2 (22-25 flm), Z2 Pulvillus with lobed dorsal component and larger ventral and Z5 (26-27flm). Four pairs ofgland pores (gd6-9) and caruncle as shown in the partially retracted puvillus and one pair of supernumerary gland pores internal to gd8 claws oftarsus IV in Fig. 10. Telotarsal setae ad1/pd1 not (overlying dark tissue mass in lactic acid macerated extending beyond the anterior margin of the ambulacral specimens). Normally 8 pairs of poroids present, idm1 stalk. Chaetotaxy offemora, genua and tibiae as follows: associated with gd6 conspicuously absent (cf Figs. 1 & Femora (I-IV) (2-5/4-2); (2-5/3-1); (1-3/1-1); (1-3/1-1). 14). Surface of shield reticulate; five paired groups of Genua (I-IV) (2-3/2,3/1-2); (2-311,2/1-2); (2-211,211-1); sigilla indicating the dorsal attachment sites offive pairs (2-2/1,311-1). of dorso-ventral opisthosomatic muscles. Lateral Tibiae (I-IV) (2-3/2,311-2): (2-2/1,211-2); (2-111,211-1); unsclerotized cuticle bearing setae SI and S3-5 and two (2-111,3/1-2). rows of marginal setae. Coxae Il with weak anterior spine. Tarsus I with distal Ventrally, tritosternum biramous with laciniae distinctly sensory field comprising 12 blunt-ended chemoreceptors, pilose, apical pilae long and extending well beyond tip a characteristic goose-neck sensillus, inflated distally and oflaciniae (Fig. 4). Sternal shield, 210-231 flm in length ending in a fine process, and a number ofmechanorecep­ and 81-92 flm in maximum width, weakly ornamented and torswith pointed tips (Fig. 11). Tarsi Il-IV with four with the normal four pairs of setae (stl-4) but only two basitarsal and 12 telotarsal setae, majority of setae with pairs of lyrifissures (ivl-2). Lyrifissure iv2 typically obli­ one to three barbules. que and removed from margin of shield. Sternal shield Locality: known only from deuteronymphs found under not fused with the endopodalia between coxae I-Il, Il-III the elytra of the following species of Carabidae in and Ill-IV. Opisthogaster with six longitudinal rows of Belgium: Agonum versutum (GYLLENHAL), Pterostichus setae forming three paired series, inner series each with diligens (STURM) and Pterostichus minor (GYLLENHAL) 5 setae, medial series normally each with five setae but collected in traps at the borders ofa pond, "Les Eplattis", anterior seta (Zv1 sensu LINDQUIST & EVANS, 1965) Ardenne; A. versutum from borders of a pond CEtang de sometimes absent, and outer series very variable with 0-3 Luchy), Ardenne; Pterostichus versicolor (STURM) from setae (Fig. 4). Four platelets posterior to genital setae (st5 a sandy moor, Vallee du Zijpbeek, C,ampine. Holotype of some authors) and one pair posterior to first pair of from A. versutum, collecting station "Les Eplattis", postgenital setae. One ofthe pair of iv5 "poroids" rarely Ardenne (locality: 5° 18' 36", 49° 45' 43") and deposited with a microseta (Fig. 4). Inguinal gland platelet with two with paratypes in the Institut Royal des Sciences pores (gv2). One pair of metapodal shields. Anal shield Naturelles de Belgique, Brussels; paratypes also in the col­ (78-90 flm long and 60-72flm wide at the level of the lections of The Natural History Museum, London. adanal setae) reticulate except for cribrum, paranal gland Deuteronymphs of H. carabidophila have been found, pores (gv3) conspicuous. Podalia of acetabulum IV each on a single occasion, with those of Halodarcia strongly developed. Peritreme short, about 75-95flm in incideta (= H. porolata sensu KARG (1969) under the length and extending to the level of the posterior third elytra ofAgonum versutum, Pterostichus diligens, P. minor of coxa Il, of characteristic form with peritreme floor and P. versicolor (FAIN et al., 1995). divided by sclerotized ridges, micropapillae not dense (Fig. 5). Peritrematic shield free and extending to the level ofpodonotal seta z3; gd10 large, associated with a group A new phoretic deuteronymph of Haladarcia KARG 65

2

3

Halodarcia carabidophila sp. nov., deuteronymph. Fig. 1. Dorsum of idiosoma showing chaetotaxy, adenotaxy (open circles), poroidotaxy (black circles and ellipses) and sigilla (dotted areas). Figs. 2 & 3. Variations in the setal complement ofthe opisthonotal shield.

Relationship to other species of Haladarcia (2) Deuteronymph of H. incideta (Fig. 12) and female of H. paralata with additional "gland" pores lying between gd2 and gd5; supernumerary "gland" pores absent in An examination of the type material of adults and nym­ the deuteronymph of H. paralata and both sexes of phal instars ofH. paralata and H. incideta indicated the H. incideta. probable incorrect assignment of the deuteronymphs to (3) Setae ofdorsal shield(s) in the protonymph and female their adults. This conclusion is based on the following ofH. paralata and the deuteronymph ofH. incideta (series observations on the labelled type specimens: A) are consistently longer than in the protonymph and (1) Setae s4 are present on the podonotal shield of the female ofH. incideta and the deuteronymph ofH. paralata deuteronymph of H. incideta (Fig. 12) and the female of (series B). For example, the lengths of z5 and J1 (z5/J1) H. paralata (male not seen) but lie off the shield in the in the protonymph, female and deuteronymph of series deuteronymph of H. paralata (cf Fig. 1) and the female A are, respectively, 43/28, 36/29, 35/30,um and in series of H. incideta. B. 25/21, 27/24, 26/24. 66 G.O. EVANS & A. FAIN

was not possible to determine with certainty the number ofporoids in H. parolata. The chaetotaxy, adenotaxy and poroidotaxy of the podonotal shield in H. incideta is the same as in H. carabidophila but, as stated above, in H. paralata setae s4 occur on the shield and not on the lateral striated cuticle as in the other two species, there are additional "gland" pores lying between setae gd2 and gd5 (three on the right side and one on the left side in the paratype examined by us) and the setae of both dorsal shields are longer and stronger (thorn-like) in H. poralata, for example, jl (30,um), z5 (36,um) and Z5(34,um). Setae zllie offthe podonotal shield in all three species. The form of the dorsal idiosomatic setae in the adults of H. poralata and H. incideta differ from those of their immature instars. In H. incideta, all the setae are spinose with the marginal series distinctly pHose whereas the stout pHose spine-like setae (Fig. 14) in H. poralata are longer and more numerous than the setiform type (Fig. 15), for example, in the podonotal region ofthe holodorsal shield in the female only j5,j6,z5, and z6 are setiform. In both adults, the gland pores (and supernumerary "gland" pores in H. porolata) are large and conspicuous. The holotype female of H. incideta has setae S4 off the shield on the left side of the idiosoma and the surface of the lateral striated cuticle is produced into rounded tubercles reminis­ cent of the lobes on the cuticular ridges of some Tetranychidae (Fig. 22). They are not present in the deuteronymph or male. Ventrally, differences are seen in the orientation of the Halodarcia carabidophila sp. nov., deuteronymph. Fig. 4. Venter second pair of deuteronymphal sternallyrifissures (iv2) of idiosoma. Fig. 5. Floor of peritreme. Fig. 6. Peritreme and which are directed longitudinally along the lateral margins peritrematic shield in lateral view. ofthe shield in both H. incideta and porolata as opposed to oblique and removed from the margin ofthe shield in H. carabidophila. The absence of gland pores iv3 is a feature of the deuteronymphs and apparently also the Data on the slide labels suggest that nymphs and adults} adults of Halodarcia. H. carabidophila is exceptional in ofboth species were recovered from the same sample (con­ having a much reduced peritreme measuring less than firmed by Dr KARG). On the basis of the above mor­ 95,um in length compared with over l30,um in H. incideta phological criteria, we consider that the deuteronymph and porolata. The floor of the peritrematic canal has a of H. paralata sensu KARG (1969) is that of Haladarcia few lateral ridges in H. porolata whereas no distinct ridges incideta KARG 1969 and that the deuteronymph of occur in the peritreme of H. incideta. Gland pores gdl0 H. incideta sensu KARG 1969 is that of Haladarcia are present in all three species. paralata KARG 1969. The following citations of the two The teeth ofthe more slender cheliceral digits, especially species of deuteronymphs refer to their emended tax­ of the fixed digit, of the deuteronymphs of H. incideta onomic status. (Fig. 16) and H. porolata are larger and stronger than in The deuteronymph of Haladarcia carabidaphila sp. novo H. carabidophila. The form of the gnathotecta is shown can be distinguished from the same instar ofthe other two in Figs. 17 and 18. The subcapitular rows ofdenticles are species of the genus by a number of morphological broader and the denticles larger in H. porolata (Fig. 19) characters. The most obvious relates to the chaetotaxy than in H. incideta which resembles the condition in H. of the opisthonotal shield which in H. incideta and carabidophila. H. paralata normally bears 13 pairs of setae (Fig. 13) The podomeric chaetotaxy is constant in the genus as is through the addition ofSI,S3 and S4 to the normal com­ the presence of the goose-neck sensillus of tarsus I in plement occurring in H. carabidaphila. Rarely, S3 may nymphs and adults. Long acuminate ventro-lateral pro­ be located on lateral unsclerotized cuticle on only one side cesses ofthe ambulacral stalk, the paradactyli, are absent of the body. The four pairs of opisthonotal gland pores in all deuteronymphs but are present on legs II -IV in the and one pair of accessory gland pores are present in the protonymph and adult (Figs. 20, 21). The two processes three species but in H. incideta 11 pairs of poroids occur retain their position when the pulvillus is retracted. The on the shield, including idml (Fig. 13). Unfortunately, it anterior acuminate process is usually longer than the A new phoretic deuteronymph of Halodarcia KARG 67

9

r , , - ~ -

Halodarcia carabidophila sp. nov., deuteronymph. Fig. 7. Chelicera showing variation in dentition ofrnovable digit. Fig. 8. Gnathotec­ turn. Fig. 9. Venter ofsubcapitulurn. Fig. 10. Arnbulacrurn oftarsus 11. Fig. 11. Sensory field oftarsus I showing goose-neck sensillus. 68 G.O. EVANS & A. FAIN

0 18 0

0

1 r 0 j5 j4 °1 .. 15

o-.gd6 o '-idm1 • .' I. \/ r- ., , 13 • • '\.. o \:9 , '·/~i

1.,) I 9d;" ,

Fig. 12. Podonotal region of the deuteronymph of Haladarcia paralata KARG. Fig. 13. Opisthonotal shield of the deuteronymph of Haladarcia incideta KARG. Figs 14 & 15. Dorsal setae of the female of H. paralata. Fig. 16. Chelicera of the deuteronymph of H. incideta. Figs 17 & 18. Gnathotecta of the deuteronymphs of H. incideta KARG (17) and H. paralata KARG (18). A new phoretic deuteronymph of Haladarcia KARG 69 posterior one in the adults. This condition is very evident in the male of H. incideta (male of H. paralata not examined). Tarsal setae adl and pdl are considerably longer in the protonymphs and adults than in the deuteronymphs and extend beyond the ambulacrum (Fig. 21).

The following key summarises the major diagnostic characteristics of the deuteronymphs:

1. Opisthonotal shield with normally 10 pairs of setae, SI never present on the shield (Fig. 1); peritreme reduced, less than 95 ,umin length; sternallyrifissures iv2 typically oblique and removed from lateral margin of shield (Fig. 4); cheliceral digits stout with teeth of movable digit weak (Fig. 7) ...... Haladarcia carabidaphila sp. novo Opisthonotal shield normally with 13 pairs of setae, SI present on the shield (Fig. 14); peritreme longer, at least 130,um in length; stemallyrifissures iv2 directed longitudinally along lateral margin ofshield; cheliceral Fig. 19. Subcapitular rows ofdenticles in the deuteronymph of digits relatively slender with proximal teeth ofmovable Halodarcia porolata KARG. Figs 20 & 21. Ambulacrum of digit strong (Fig. 16) 2 tarsus II of the female of Halodarcia incideta KARG in lateral 2. Podonotal shield with 15 pairs of setae, s4 on lateral (20) and ventral (21) views. Fig. 22. Terminal lobes of the unsclerotized cuticle, and without supernumerary cuticular striae of the dorso-latera1 region of the opisthosoma gland pores; subcapitular transverse rows ofdenticles of the female of H. incideta. relatively narrow, restricted to groove and with den­ ticles weak (cf. Fig. 9); median process of gnathotec­ turn long, normally bifurcate distally and extending well beyond the level ofthe antero-lateral projections (Fig. 17) -Haladarcia incideta KARG - Podonotal shield with 16 pairs of setae, s4 on shield, of the adults, the adenotaxy of the idiosoma, and the and with supernumerary gland pores; subcapitular chaetotaxy of tibia I, appear to differ from other transverse/oblique rows of denticles broader, not Halolaelapidae and are discussed below. restricted by grove and with strong denticles (Fig. 19); The fusion ofthe two dorsal shields in the deuteronymph median process of gnathotectum shorter, stouter and of Haladarcia to form a holodorsal shield in the adult is typically trifurcate distally (Fig. 18) .. atypical for other Halolaelapidae in which the podonotal ...... Haladarcia paralata KARG shield is distinct from the opisthonotal shield(s) in the adult. In fact, this scutal developmental pattern, although common in the Parasitina, is relatively rare in free-living Relationship to other Halolaelapidae Dermanyssina with the notable exception of the family Ologamasidae. The complement and arrangement ofthe KARG (1969) placed the genus Haladarcia in the family inner (l) series of setae on the opisthonotal shield in the Halolaelapidae together with the genera Halalaelaps and Halolaelapidae, as seen in the absence of setae J3 (a seta Antennaseius. The new genus shared with Halalaelaps cer­ first appearing at the larval instal') and the position of tain morphological features, such as the location of Z5 Z5 posterior to J5 are evident in Haladarcia, Halalaelaps, posterior to J5 and the absence ofJ3 on the opisthonotum , Saintdidieria and Sapralaelaps. However, J3 is and the presence ofpointed "pulvilli" ("spitzen Haftlap­ considered to be present in Saprasecans and the location pen"), which figured prominently in his diagnosis of the of Z5 posterior to J5 is common in the Laelapidae and family. The genus Antennaseius had previously been also in the Eviphididae and Pachylaelapidae which lack placed in the family Ascidae by LINDQUIST & EvANS J3. (1965) and in the Antennoseiidae by KARG (1965). This The dorsal and lateral adenotaxy in Haladarcia comprises broad concept ofthe family was retained by KARG (1971) ten pairs of gland pores (gdl-lD). The adenotaxy of the who also included within it the genera Leitneria and other Halolaelapidae has not been studied in detail and, Saprasecans. EVANS & TILL (1979) excluded Antennaseius as in the Dermanyssina as a whole, the data are patchy from the Halolaelapidae but recognized Sapralaelaps and and inadequate for comparative purposes. An unusual Saintdidieria (treated as synonyms of Halalaelaps by feature of H. paralata is the presence of supernumerary KARG) as valid genera. Certain of the morphological "gland" pores in the podonotal region of the deutero­ features of Haladarcia, such as, the dorsal sclerotization nymph and adult. All the dorsal gland pores in the adults 70 G.O. EVANS & A. FAIN of H. porolata and H. incideta are enlarged and con­ example, each ends in a flattened denticulate lobe. Unlike spicuous in contrast to the relatively small gland pores, the ambu1acrum, comprising claws and pu1villus, the other than gd8 in some species, in other Ha101ae1apidae. paradacty1i are not capable of being withdrawn into the A full complement ofporoids are present in the podonota1 ambu1acra1 stalk. The denticulate lobes appear to close and pleural (stigma, peritreme, peritrematic shield) regions over the extremity of the ambu1acra1 stalk when the in Halodarcia and Saintdidieria. Details are not available ambu1acrum is withdrawn and thereby provide a protec­ for other Ha101ae1apidae. An interesting and unique tive cover to the retracted ambu1acrum. On the basis of feature ofthe poroidotaxy ofthe intercoxa1 region ofthe their proposed function, EVANS & DLL (1965) named the deuteronymph of Halodarcia is the absence of the third lobes pretarsa1 opercula. Those species with elongate sterna1 pores (iv3). These pores normally first appear in acuminate paradactyli usually have longer tarsal setae ad1 the deuteronympha1 instar. We were unable to find them and pd1 than those with short paradactyli. in mounted type specimens of the adults which have It is apparent from the above that the genus Halodarcia suffered compression and distortion but their absence differs from other genera included in the Ha101ae1apidae requires confirmation. in at least three well-defined morphological characters: The major difference in podomeric chaetotaxy between 1) the presence of a ho1odorsa1 shield in the adults; Halodarcia and other Ha101ae1apidae is seen in the 2) six dorsal setae on the tibia and tarsus of leg I in presence of six (2-3/2-3/2-2) instead of five (2-3/2-2/2-2) deuteronymphs and adults; dorsal setae on genu and tibia I. No intrageneric varia­ 3) the absence of poroid iv3 in deuteronymphs and pro- tion was observed. The occurrence of 13 setae (four ven­ bably also adults. tra1s) on femur I also occurs in , Leitneria, On this basis, we propose the division of the family into Saprolaelaps and Saprosecans but only 12 setae are pre­ two subfamilies, the HALODARCIINAE to accom­ sent in Saintdidieria and Saprogamasellus (2-5/3-2). Dif­ modate the genus Halodarcia and the HALOLAELA­ ferences in the chaetotaxy of other podomeres in PINAE for the genera Halolaelaps, Leitneria, comparision with the condition in Halodarcia are seen on Saintdidieria, Saprogamasellus, Saprolaelaps and genu III (2-2/1-2/0-1), genu IV (2-2/1-3/0-1) and tibia IV Saprosecans. (2-111-211-1) of Saprolaelaps and Saprosecans, on genu IV (2-2/1-3/0-1) and tibia IV (2-111-2/1-2 or 2-111-3/1-1) of Halolaelaps, Leitneria and Saprogamasellus, and on genu Acknowledgements Il (2-3/0-211-2) of Saintdidieria. The prominent goose-neck sensillus oftarsus I in Halodar­ We are grateful to Dr. M. MORITZ, Museum fUr cia which distally enlarges before being drawn out into Naturkunde der Humbo1dt Universitat, Berlin for the loan a fine process, is not present in that form in Halolaelaps of type material of Halodarcia and to Dr Anne BAKER, but does occur in Leitneria, Saprolaelaps, Saprosecans and The Natural History Museum, London for the loan of Saintdidieria. This type of sensillus, however, appears ha1o1ae1apid material. widely in the Dermanyssina (and also the Parasitina), for example, within the families Macrochelidae, Pachy­ 1ae1apidae, Lae1apidae, Ascidae and Gamasellidae. The paradacty1i, present only on each of legs Il-IV, are par­ ticularly well-developed in the protonymphs and adults of Halodarcia, Halolaelaps and Saprolaelaps and in the female of Saprosecans (nymphs not examined) and form long acuminate processes extending a considerable distance beyond the ambu1acrum. Members of these genera live in damp or wet habitats and this extreme development ofthe paradacty1i and the dista1 pair ofdor­ sal tarsal setae could be an adaptation for moving over wet substrates. Their absence in deuteronymphs suggests that the normal habitat of this instar is different from other stages in the life-cycle and the phoretic relationship established between two ofthe species of deuteronymphs and carabid beetles supports this. (Differences in the form ofthe pu1villi between aphoretic females and their phoretic deuteronymphs are also apparent in the Parasitinae in which the deuteronympha1 pu1villi are disc-like and not lobate as in the adults.) Paradactyli in the Dermyssina vary considerably in shape. In the majority, they are in the form of short acuminate or lobular processes lying alongside the pu1villus in its extended state but in some taxa within the Macrochelidae and Haemogamasidae, for A new phoretic deuteronymph of Halodarcia KARG 71

References KARG, W. 1965. Larvalsystematische und phylogenetische Untersuchung sowie Revision des Systems der Gamasina Leach, ATHIAS-HENRIOT, C. 1971. La divergence neotaxique des 1915 (Acarina, Parasitiformes). Mitteilungen aus dem Zoologische Gamasides (Arachnides). Bulletin Scientifique de Bourgogne, 28: Museum in Berlin, 41: 193-340. 94-106. KARG, W. 1969. Untersuchungen zur Kenntnis der Ascaoidea ATHIAS-HENRIOT, C. 1975. Nouvelles notes sur 1es Amblyseiini, KARG, 1965 (Acarina, Parasitiformes) mit der Beschreiben von 2. Le releve organotaxique de la face dorsal adulte (Gamasides, acht neuen Arten. Zoologischer Anzeiger, 182: 393-406. Protoadeniques, Phytoseiidae). Acarologia, 17: 20-29. KARG, W. 1971. Acari (Acarina), Milben, Unterordnung Anac­ EVANS, G.O. 1963. Observations on the chaetotaxy of the legs tinochaeta (Parasitiformes). Die Freilebenden Gamasina in the free-living Gamasina (Acari: Mesostigmata). Bulletin of (Gamasides), Raubmilben. Die Tienvelt Deutschlands, 59. Gustav the British Museum (Natural History) [Zool.], 10: 275-303. Fischer Verlag, Jena, 475 pp. EVANS,G.O. & TILL, W.M. 1965. Studies on the British Der­ LINDQUIST, E.E. & EVANS, G.O. 1965. Taxonomic concepts in manyssidae (Acari: Mesostigmata). Part I. External morphology. the Ascidae, with a modified setal nomenclature for the idiosoma of the Gamasina (Acarina: Mesostigmata). Memoirs of the Bulletin of the British Museum (Natural History) [Zool.], 12: 247-294. Entomological Society of Canada, No. 47: 1-64. EVANS, G.O. & TILL, W.M. 1979. Mesostigmatic mites of Britain and Ireland (: Acari: Parasitiformes). An introduction to their external morphology and classification. Transactions ofthe Zoological Society ofLondon, 35: 139-270. 34 Hormare Crescent, Storrington FAIN, A., NOTI,M.I. & DUFRENE,M. 1995. Observations on the West Sussex, RH20 4QT, U.K. mites (Acari) associated with Carabidae (Coleoptera) in Belgium. Department Entomology, 1. Annotated list of the species. International Journal of Royal Belgian Institute for Natural Sciences Acarology, 21: 107-122. Brussels, Belgium