PSYCHE. THE SEGMENTATION OF THE INSECT HEAD.

BY JUSTUS WATSON I:rOLSOM, CAMBRIDGE, MASS. The elucidation of the primitive Huxley, as the most probable. Cho- segments in is a most inter- lodkovsky is of a similar opinion." esting and difficult morphological Packard ('98) gives six: problem. The rule of Savigny-- Seg'rnent. Aflflendag'es, etc. emphasized by Huxley and others-- Ocellar (Protocerebral). Compound and simple eyes. that arthropods are fundamentally con- Antennal(Deutocerebral). Antennae. 3. Premandibular, inter- Premandibular append- structed of successive rings, each of calary (Tritocerebral). ages. which may bear but one pair of pri- ,. Mandibular. Mandibles. S. First Maxillary. First Maxillae. mary appendages, although now un- 6. Second Maxillary. Second Maxillae, Lab- doubted, has never been thoroughly ium. Post-gula, gula, submentum, hypopha- substantiated when applied to the rynx, (lingua, ligula), hexapod head. After )Tears of argu- paraglossae, spinneret. ment, morphologists still disagree as to Upon anatomical grounds, different the number of somites composing the observers have recognized from one to highly differentiated heads of insects, seven head segments. As mentioned Compare the latest text-books in respect by Packard ('98), Burmeister found to the subject. Kolbe ('9o) recognizes only two Carus and Audouin three; five, as follows: MacLeay and Newman four; Straus- . Ursegment Ftihler Augen, Oberlippe. Durckheim seven. Huxley ('77) said, 2. Oberkiefer oder Mandibeln. "It is hardly open to doubt that the 3. Unterkiefer oder Maxillen. mandibles, the maxillae, and the labium, [4. Zunge oder Innenlippe.] answer, to the mandibles and the two Unterlippe. 5. pairs of maxillae of the Sharp ('95) says, "Morphologists mouth. In this case, one pair of are not yet agreed as to their number, antennary organs found in the latter is some thinking this is three while others wanting in insects, as in other air- place it as high as seven" three or four breathing arthropods, and the existence being, perhaps, the figures at present of the corresponding somite cannot be most in favour, though Viallanes, who proved. But if it be supposed to be has recently discussed the subject, con- present, though without any appendage, siders six, the number suggested by and if the eyes be taken to represent 392 los YCHE. [August x$99. the appendages of another somite, the in (Wheeler '93, Claypole insect-head will contain six somites." '98) and Campodea (Uzel '97), and Huxley's conclusions were the most the last two authors have homologized satisfactory that could be derived from them with the crustaceaa second a study of the completed organs alone antennae. I may add that rudimentary and reduced the problem to these ques- chitinized intercalary appendages per- tions- Do the eyes represent a somite sist in adults of Tomocerus, Orchesella Is another antennal segment represented and other Collembola. in insects? Do the labrum and hypo- Six cephalic somites are the most pharynx represent distinct segments ? that have been admitted upon embryo- Authors began to realize the impossi- logical grounds--but I am convinced bility of settling the problem upon that six are not adequate. To prove purely anatomical data and attacked it this statement, I must give a prelimi- from the embryological side. Packard nary summary of some recent studies ('7), followed by Graber ('79), found upon the anatomy and development of four cephalic somites: antennal, man- apterygote mouth-parts. dibular, first and second maxillary. The hypopharynx in Collembola and Viallanes ('87) however, wrote the Thysanura consists of three parts: a most important contribution upon the median ventral lingua and two dorso- subject after studying the development lateral su2berlinguae hitherto termed of the nervous system in insects and " paraglossae," but quite distinct from decapod crustacea, and summarized his the labial structures with the same results as follows. name. In the embryo of Anurida " La tSte de 1' Insecte est forme par tnaritima, the superlinguae originate as six zoonites, trois sont prbuccaux et a pair of simple papillae between the trois post-buccaux. Le premier zoonite mandibles and first maxillae and slightly porte les yeux composs et les ocelles. nearer the median plane. The super- Le deuxiime les antennes. Le trois- lingual anlagen are ectodermal evagi- igme, qui est d6pourvu d'appendices, nations containing intrusive mesoderm porte le labre, pi6ce qui, pas plus chez and are histologically undistinguishable les Insectes que chez les crustacs, ne from the anlagen of the remaining peut 8tre consid6r6e comme le r6sultat appendages. The lingua appears as a de la soudure de deux appendices. Le subsequent and quite independent quatl'ibme zoonite porte les mandibules, median evagination of the first maxil- le cinquime les mg.choires, le sixiime lary segment and becomes supported la lgvre infrieure." These conclusions by a pair of lateral chitinous stalks have been confirmed by Wheeler ('93), which originate in superficial grooves Heymons ('95, '97) and others. of the germ band. Rudimentary intercalary, or preman- Soon after involution has occurred, dibular, appendages have been found just seven pairs of cephalic ganglia are August 899. .PS 393 seen and--important facts- the third including Hemimerus (Hansen '94). pair belongs to the intercalary segment Miall and Denny ('86) have figured and the fifth to the superlingual somite. them for Periplaneta and I have found The lingua has no ganglia. Later, the them clearly in Melanoplus femoratus. first three pairs unite to form the supra- There are striking and detailed agree- and the remaining four, the suboeso- ments between the anterior somites of phageal ganglion. insects and decapod crustacea. Vial- More conclusive proof that the inter- lanes ('87) and Hansen ('93) have calary and superlingual appendages emphasized the fact fi'om their respec- represent primitive segments, of which tive standpoints of embryology and there are seven, could hardly be comparative anatomy. My own results, expected. confirming and supplementing their In Campodea (Uzel '98) and Ephe- views, may partially be expressed in mera (Heymons '96) the hypopharynx tabular form. Between such divergent originates as three independent anlagen groups, of course, homologies indicate and several authors have held it to nothing nore than a parallelism in represent a somite upon anatomical development. grounds. The hypopharynx of highly EQUIVALENT PAIRED ORGANS. specialized insects, however, I find to iXe ITre be homologous with simply the lingua Som aoda Cruslac Compound eyes Compound eyes of Collembola and Thysnura, although Antennae Antennules the superlinguae are represented in the Intercalary appendages Antennae 4 Man dible Mandibles more generalized Pterygota but have Superlinguae First Maxillae usually been overlooked or disregarded. First Maxillae Second Maxillae Among the lingua and Labium First Maxillipede superlinguae do not unite, although WORKS CITED. their three cavities become con- basally Claypole, A. M. '98. The Embryology fluent with the general body cavity. and Oggenesis of Anurida maritima (Gudr.). In Orthoptera and Ephemeridae, how- Jour. morph., vol. I4. ever, the superlinguae are firmly united Hansen, H. J. '93. Zur Morphologie der with the lingua. Although often con- Gliedmassen und Mundtheile bei Crustaceen und Insecten. Zool. anz. spicuous in the latter group (Vayssi6re jhg. x6. Hansen, H. J. '94. On the Structure and 'Sz), the superlinguae are less so in Habits of Hemimerus talpoides Walk. En- Orthoptera but I have found them as tom. tidsk, arg. 5. distinct lobes in all families of the Heymons, R. '95. Die Segmentirung des order. The chitinous lingual stalks, Insectenk6rpers. Abh. preuss, akad. wiss. important in Collembola and Cam- Berlin. Heymons, R. Grundztige der Ent- become reduced and function- '96. podea, wickelung und des Kirperbaues yon Odona- less in Machilis and Lepisma but occur ten und Ephemeriden. Abh. preuss, akad- as rudiments even in Orthoptera, wiss. Berlin. 394 t:'S YCI.E. [August x899.

Heymons, R. '97. Entwicklungsgeschicht- Uzel, H. '97. Vorliufige Mittheilung tiber liche Untersuchungen an Lepisma sacchar- die Entwicklung der Thysanuren. Zool. anz. ina L. Zeits. wiss. zool. bd. 6.. bd. 2o. Huxley, T. H. '77. A Manual of the Uzel, H '98. Studien tiber die Entwicklung Anatomy of Invertebrated . der apterygoten Insecten. Berlin. Kolbe, H. J. '89-'93. Einfiihrung in die Vayssire, A. '82. Recherches sur l'or- Kenntnis der Insekten. ganization des larves des ]phdm(!rines. Ann. Miall, L. C. and Denny, A. '86. The sc. nat. zool. sdr. 6, t. 13. Structure and Life-history of the Cockroach. Viallanes, A. '87. tudes histologiques Packard, A. S. '71. Embryological Studies et organologiques sur les centres nerveux et on Diplax, Perithemis, and the Thysanurous les organes des sens des animaux articuls, Genus Isotoma. Mem. Peab. acad. sc. no. 2. Ann. sc. nat. zool. sdr. 7, t. 4. Packard, A. S. '98. A Text-book of Ento- Wheeler, W. M. '93. A contribution to mology. Insect Embryology. Jour. morph, vol. 8. Sharp, D. '95. Insecta. Camb. nat. hist.

DESCRIPTIONS OF THREE NEW SPECIES OF ALEURODIDAE FROM BRAZIL.

BY ADOLPH HEMPEL S. PAULO BRAZIL.

Aleurodes korrldus n. sp.- Pupa-case.- Adult .--1.o8 mm. long, yellow, eyes Length, mm. elliptical in outline, flat; black; wings transparent, yellowish, covered light yellow in color. The dorsal surface is with a white powder. Antennae of seven covered with white secretion, arranged in joints. Joints 3-7 fine, cylindrical, slender; a median longitudinal row, and a submar- joint 2 large, club-shaped. Legs long and ginal row on each side. Around the margin slender, nearly reaching to the apex of the there is also a very short fringe of white closed wings. wax, These details are however obscured Hab.--On the underside of leaves of by a mass of long yellowish, hair-like secre- guava, Psidium sp., from S. Paulo, Brazil. tion, that envelopes each individual. De- Accompanied by a species of dnt (Cremas- nuded of wax, the margin is found to be togaster). doubly crenulated, with the posterior end of Aleurodesfunijbennis n. sp.--Puba-case.-- the body rounded and the anterior end Elliptical, convex, black, 1.8 ram. long. forming an obtuse angle. The dorsum is There is a prominent median longitudinal, slightly wrinkled, and has a short median dorsal ridge, and about six transverse fur- longitudinal ridge, extending from the ante- rows. The lateral margin is thick with a rior end to nearly the middle of the body. conspicuous groove on the dorsal surface Vasiform orifice subelliptical, broader and a short fringe of white wax on the ven- than long. Operculum hemispherical, tral surface. Near the posterior end, around nearly fitting the orifice, the free end the vasiform orifice, there is a large hemi- notched. A long seta is situated on each spherical area, nearly transparent, but dusted side of the orifice; two on the caudal end with white secretion. The lateral margin is of the body; and two on the ventral surface slightly notched in places, but not crenu- of the body just cephalad of the middle. lated. Vasiform orifice hemispherical No traces of antennae or legs were found. operculum small, rectangular, fitting the International Journal of Peptides

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