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University of Illinois Library MAY 2 0/1969 L161—O-1096 A Sy a j 4 it J “ate; "V4 ieee SAINT Digitized by the Internet Archive In 2011 with funding from University of INinois Urbana-Champaign http://www.archive.org/details/neadcapsuleofcol08stic ILLINOIS BIOLOGICAL MONOGRAPHS PUBLISHED QUARTERLY UNDER THE AUSPICES OF THE GRADUATE SCHOOL BY THE UNIVERSITY OF ILLINOIS VOLUME VIII Urbana, Illinois 1923 EDITORIAL COMMITTEE STEPHEN ALFRED FORBES HENRY BALDWIN WARD ce c< ce c WILLIAM TRELEASE u. sua 77 OY YL TABLE OF CONTENTS VOLUME VIII NUMBERS PAGES 1. The head-capsule of Coleoptera. By F. S. Stickney. With 26 plates.... 1-104 2. Comparative studies on certain features of Nematodes and their sig- nificance. By D. C. Hetherington. With 4 plates................. 105-166 3. Parasitic fungi from British Guiana and Trinidad. By F. L. Stevens. RUNCREED ARPES OBS Nodak th ok Sal Page cael A Re Meer de einige oie MORO 167-242 4. The external Morphology and Postembryology of Noctuid Larvae. By 243-344 Fe BaRipleye. With Splatest.:/cx ancy eects a eee areereteraeze ny Dacca ‘ . ots f ae Shakeela Adige Ree | ae be Peet thi va Rl hulaicntiinn’ bin dain ‘eae eth ORT ae emia ohn atl ILLINOIS BIOLOGICAL MONOGRAPHS Vol. VIII January, 1923 No. 1 EDITORIAL COMMITTEE STEPHEN ALFRED FORBES WILLIAM TRELEASE HENRY BALDWIN WARD PUBLISHED UNDER THE AUSPICES OF THE GRADUATE SCHOOL BY THE UNIVERSITY OF ILLINOIS PRESS CopyricHT, 1923 By THE UNIVERSITY OF ILLINOIS DISTRIBUTED JUNE 20, 1923 THE HEAD-CAPSULE OF COLEOPTERA WITH TWENTY-SIX PLATES BY FENNER SATTERTHWAITE STICKNEY Contributions from the : Entomological iaeeeatares a oe University of Illinois 0. THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN ENTOMOLOGY IN THE GRADUATE SCHOOL OF THE UNIVERSITY OF ILLINOIS 1921 TABLE OF CONTENTS are TELSFC ETOCS Se Cys I eee a aoe ese Ree se i lsat chiens EM if ERIN RERE eh es Tai na So al tie with er 2d io Sane ep OAL e Soe Mahle Mirae ata Daal ee 9 TPE DITA] aE sR SRS eran se, Nae et 0 eet Bell eat a ae” a ee ene a Rea 10 IN ee en he LNs penn AN lego A oy an arg Ai BN) pal NOIDA a6 408.9 16 eUMORA EAMES rx ay SG as, Zeke ion ae a aiako tc ee ae PR eee 17 SS ay eth Soret an he SS OR CST) 69 Rhea ONer BE Le MLean NCR SO. © gE TERE FSS Rene 20 MRNA RA Or) esi rc lac 8s ME va ave ea el stake Ndi s mamta © Sloe @ ea 21 (|e Ses Rie ae nit er UAE ae Pt Si A eR ND Beas: 21 EMME Pe he en a kU RELA reeset state Ware Wn ce ei wley aed eee aaa ae 22 CUTE eet POPS ater e OMe APU A PUES Ran Uy, Ridka aivits oi aia chee seme eee Ne 22 SINT MMN SR CTIRIRS 2 ce ord) c 2. gan Miah, HNL VAI ors tates oak aS ay eee vie aatne 22 Degas SG BI eae WE Zoe mre mn Eg BREE) Br nv Ra PR Coa A Prk 23 JS) STD TEED AR RI A ee PS a et TE i PO A AC 23 POMEL TEORLAP Ty Us eet ee Fes to natn ee cecee ee ape ee Sine Brite sa keh s eyytetee eles Re pen cig sla ucts za 23 SRL UCUM aCe Ny Ne neers a Cares sek ape aat hare, orth chabsna cae rdbaiteldieaa ahem wueye camel e 23 RSrEECHEOTITI ACG ty Ft Hare ne eel PT eS a ied ook i tue Me Se reece Sd oe ec NERD aul tae 23 TRENT Ce Ohne An ae See ee Re oD ORO eco 2A eR ern Ore oieneeete 24 EES SE Te ROU NN TSR ope af UE Rim SGN POMP PE eee ty apie 25 Lo aS SR A i RI Si a UES FAC rl ReaD UR EO Seen Re Ror aaron aa 25 CT EIR oS appt ah laude peace lh cali eed Bo Sty RR eer an ener pS) Ste Si Sa 25 NVERHCUISIIARAA eS Hehe tl eh Gee a te rate re tases aed Ue Se ee TEE RIO sts 26 Rem eet IN. AA icc Retna te MN ee, SED A cleat ig Ca ROME gw el ara 26 LATE g Pers 68 ee ere Nene onParE ho Rt pane irs Sane Seen eee ee ame nce Ne aie eee 26 ER STRAPS 08h 2 RO pect 6s a ohana thee bg ahd a ecigse eho Cie eee 27 Sara Coe Pea we ee ter cm 2 all a ee ee ee tO eet et 27 MVR EAEREL COLES erred oer ety ret Hee eed act, wet uyenra the tala Suara Yiu apap ert 28 RTE Se Sema Se Rr eae BGS Pe ARETE ome reps ey Pairs ee ay Guniain Aeae SEO 29 SET IGANSCLERICES eget bite ts ee Ree tes Diet pene sO US Oe aaa 29 A QTEOIG EA Sp ee DT Becks AAP sake Hib tah 9 oto), Waka) OE Uae s oelel e 30 LEFDSTIS peal pea SO Raa aR De CR amg pam OVE ps APSE eal are OER anes Se Cn a Ft 30 SUT TS RLM es OER I oh eet ne ge RR Ra ec gH & en eet Drei RSE MRT 32 WPMUE ERIM ee ne ao nye Shee Lian ial iu) teeta Syste wre oy gate, sie Specs MBN 34 PAY ACOU AM RR ee oie ee ee URINE lee a MM ME Aca aia vader Met 34 IResteoilaya ss ee ee Lies Re De OE. eed OO ERNE, No ae 34 ERR GT De ARMS ME ae aN rane eee ts Sete ee NE gee ah Ae aT OEM Ale ee ch ea A 34 DES TTU TT aha 0 goa deere Dk RN we Et a pc uNen es OU Oe AY 8. RCE We ERE 35 PITELEMGONININ IR ste rc ASE AF tanh tae nT CG ATTA Tena carne eRn bas) Oaeat a t 36 VEGETAL EO LORIUEAT ren re ter ieee ea aii esrel te Ainag eed hie tel ebtoe oh sbens bata olie es trate 37 5 Se TS AAR OR el We OR a oe Pr SO a ea er se 37 ANEASTYAETLG TITAS oe tee Se eee eI Te hia tals A cases aeaas 38 Reine HIN RAR Ede) hctah Seal Shout vic sh pene ak ait Alva cl moghavatate le 2 Meiees' Rebar tia 39 Sere Pivlopenetic Consitlerations. . 5). 5 i..c0 ce cieiacees es oso niaine aw aes) oia Og wale petepmen ee 40 SLLEEE TTT Ae NPA Sy eS I Ue ee Ae RU Heme emai eta cRecY 48 jf Ne PS 7 Py) y = ™ a ss Neh > y . Ae bine Mathie vay Brit , “6 RRND YAN DY 7] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 7 INTRODUCTION LeConte and Horn published in 1883 a classification of the Coleoptera that has stood the wear of time remarkably well. Since then, however, a number of new classifications have been proposed: Lameere (1900 and 1903), Ganglbauer (1892-1904), Handlirsch (1906-1908), Kolbe (1901, 1908, and 1911), Sharp (1909), and Gahan (1911), all of which differ more or less seriously in one way or another, and show, for one thing, the need of further comparative morphological data, which is, of course, indispensa- ble to the building of any thorough classification. Leng’s recent catalogue (1920) also emphasizes this need. A review of the literature seems to show but few studies based on the comparative morphology of a comprehensive series of coleopterous fami- lies. A number of European workers have published comparative studies of the wings of Coleoptera, the most recent being by d’Orchymont (1920). Sharp and Muir (1912) and Muir (1918) have published the results of their investigations on the male geirital tube in Coleoptera. Various internal structures have been discussed-from time to time by a number of workers. Narrower in scope is the work’ of d’Orchymont (1916) on the classification of the Hydrophiloidea, based on’a study of both the adult and the larva. Hyslop (1917), Béving and Champlain (1920), Craighead (1920), and Gage (1920) have published papers on the comparative mor- phology of various families, based on a study of the larvae. There are prob- ably other comparative papers more or less extensive in scope, but I have not been able to find any such literature based on a study of the head- capsule, though Crampton (1917, 1920, and 1921) has included the discus- sion of the coleopterous head in papers not limited to a single order. The comparative morphology of the head-capsule of some other orders, how- ever, has been investigated: Peterson (1915) on the Thysanoptera, Peter- son (1916) on the Diptera, Yuasa (1920) on the Orthoptera, and Hoke (1923) on the Plecoptera. These simply draw attention to the need of such an investigation of the head-capsule of Coleoptera. With the broader vision in mind of a more satisfactory and natural classification of the Coleoptera, the following study on the comparative morphology of the head-capsule is offered. This study does not aim by any means to exhaust the subject. There have been too few species in- vestigated in each family to justify the making of any sweeping state- ments. This study can simply point out characteristic conditions of structures as found in the different species of the families studied, revealing, 8 ILLINOIS BIOLOGICAL MONOGRAPHS [8 therefore, inharmonies, and perhaps suggesting improvements on the pres- ent arrangement of the classification. In order to reach a correct estimate of the degree of specialization of the various parts of the head-capsule, an hypothetical type, representing a supposed primitive condition, has been constructed. The structure of this hypothetical type is based on the structure of the head-capsule of generalized insects and of generalized adult and larval Coleoptera. Each structure has been treated separately, starting from the hypothetical type. The submentum has been included in this study because of its bearing on certain developmental processes. All statements made refer to the species listed under “materials” only. The material studied was soaked in a 10% solution of potassium hydroxide until clarified, then washed in distilled water to remove the hydroxide, and preserved in 70% alcohol. All dis- sections were made under a binocular microscope in 70% alcohol in Syra- cuse watch-glasses. 9] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 9 ACKNOWLEDGMENTS This study was pursued under the supervision of Professor Alex. D. MacGillivray, to whom I am under the deepest obligations for all that his supervision has meant to me in the way of helpful suggestions and real inspiration. I must further thank him for permission to use his unpub- lished morphological nomenclature. I am also greatly indebted to Profes- sor S. A. Forbes for suggestions and for furnishing a large number of species from the collections of the Illinois State Natural History Survey and from the collections of the University of Illinois. I am further greatly indebted to Professor H. F. Wickham of the Iowa State University, who supplied me with a considerable number of species belonging to rare families; to Messrs. E. A. Schwarz and H. S. Barber, and the authorities of the United States National Museum for representatives of twelve very rare families from the collections of the Museum; to Mr. W. S. Blatchley of Indianapolis for many very rare species; to Dr. Edwin C. Van Dyke of the University of California for a specimen of a species of Othnius; and to Professor Henry C. Fall for a specimen of Hydroscapha. Of the many courtesies that Dr. Chas. P. Alexander of the Illinois State Natural History Survey has shown me I am duly appreciative. Finally, to Mrs. Elizabeth Stick- ney, who has helped me greatly in the preparation of the drawings, I am under deep obligations. 10 ILLINOIS BIOLOGICAL MONOGRAPHS [10 MATERIALS An effort has been made to make this study as comprehensive as pos- sible, including not only a wide series of families, but also a representation of the different subgroups within the families. Of the eighty-one families, exclusive of the Strepsiptera, listed by LeConte and Horn, representatives of all are embraced in this study. Leng in his recent catalogue lists one hundred and nine families. Of these one hundred and five have been stud- ied and figured, representing one hundred and forty-six species. The fami- lies in Leng’s catalog not included in this study are Telegeusidae with one species, Cerophytidae with two species, Murmidiidae with five species, and Monoedidae with one species. The fundamental structure of the ead is, except in a few cases, practically similar for the two sexes. The sex has, therefore, been disregarded, except in the case of the brenthid, Eupsalis minuta, the female of which has a long slender snout, as contrasted with the large broad snout of the male. The latter has been figured. A numberof attempts were made to arrange the figures in a linear series leading from the generalized to the specialized forms. All attempts proved unsatisfactory. No matter what structure or condition of a struc- ture was used, the structure showed itself to be unstable within narrow limits, and therefore could not be relied upon to illustrate a definite line of development. However, the meagre results obtained in trying to ar- range the drawings in a linear series emphasized an important fact: that the various families of Coleoptera and even the subgroups within the families, have developed along many lines. For this study, the arrange- ment finally decided on, including the species, is that adopted by Leng. This arrangement will be valuable, in so far as the head-capsule is con- cerned, in showing the need for further morphological work towards the improvement of our classification of the Coleoptera. Owing to the number of drawings presented in this study it was deemed more practical to omit detailed descriptions. The salient features, only, of the various structures are discussed. The following list is arranged according to Leng’s catalog, and includes only those species figured :— COLEOPTERA SUBORDER ADEPHAGA CARABOIDEA. 1. Cicindelidae. Megacephalini.—Tetracha carolina (Figs. 2, 150, 297, 444). Cicindelini.—Cicindela formosa (Figs. 3, 151, 298, 445). 11] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 11 2. Carabidae. Carabinae.—Calosoma calidum (Figs. 4, 152, 299, 446). Harpalinae—Harpalus erraticus (Figs. 5, 23, 24, 153, 300, 447). . Amphizoidae——Amphizoa lecontei (Figs. 6, 154, 301, 448). . Omophronidae—Omophron americanum (Figs. 7, 155, 302, 449). . Haliplidae—Peltodytes 12-punctatus (Figs. 8, 156, 303, 450). 6. Dytiscidae.—Cybister fimbriolatus (Figs. 9, 157, 304, 451). GYRINOIDEA. 7. Gyrinidae.—Dineutes americanus (Figs. 10, 158, 305, 452). wn qe Go SUBORDER POLYPHAGA HYDROPHILOIDEA. 8. Hydrophilidae. Hydraeninae.—Hydraena marginicollis (Figs. 11, 159, 306, 453). Hydroscaphinae.—Hydroscapha natans (Figs. 12, 160, 307, 454). Hydrophilinae——Hydrous triangularis (Figs. 13, 161, 308, 455). Hydrophilus obtusatus (Figs. 14, 162, 309, 456). SILPHOIDEA. 9. Platypsyllidae—Platypsyllus castoris (Figs. 15, 163, 310, 457). 10. Brathinidae——Brathinus nitidus (Figs. 16, 164, 311, 458). 11. Leptinidae——Leptinus testaceus (Figs. 17, 165, 312, 459). 12. Silphidae—Necrophorus carolinus (Figs. 18, 166, 313, 460). 13. Clambidae—Clambus puberulus (Figs. 19, 167, 314, 461). 14. Scydmaenidae.—Connophron fossiger (Figs. 20, 168, 315, 462). 15. Orthoperidae.—Molamba lunata (Figs. 21, 169, 316). STAPHYLINOIDEA. 16. Staphylinidae. Steninae.—Stenus flavicornis (Figs. 22, 170, 317, 463). Paederinae.—Gastrolobium bicolor (Figs. 25, 171, 318, 464). Staphylininae—Creophilus villosus (Figs. 26, 172, 319, 465). Tachyporinae.—Tachinus fimbriatus (Figs. 27, 173, 320, 466). Aleocharinae.—Aleochara lata (Figs. 28, 174, 321, 467). 17. Pselaphidae.—Pilopius lacustris (Figs. 29, 175, 322, 468). 18. Clavigeridae.—Fustiger fuchsi (Figs. 30, 176, 323). 19. Ptilidae—Limulodes paradoxus (Figs. 31, 177, 324, 469). 20. Sphaeriidae.—Sphaerius politus (Figs. 32, 178, 325, 470). 21. Scaphidiidae —Scaphidium quadriguttatum (Figs. 33, 179, 326, 471). 22. Sphaeritidae——Sphaerites glabratus (Figs. 34, 180, 327, 472). 23. Histeridae.—Hister memnonius (Figs. 35, 181, 328, 473). CANTHAROIDEA. 24. Lycidae.—Calopteron terminale (Figs. 36, 182, 329, 474). 25. Lampyridae.——Photinus pyralis (Figs. 37, 183, 330, 475). 26. Phengodidae.—Phengodes plumosa (Figs. 38, 184, 331, 476). 12 ILLINOIS BIOLOGICAL MONOGRAPHS {12 27. Cantharidae. Chauliognathini—Chauliognathus pennsylvanicus (Figs. 39, 185, 186, 332, 477). Cantharini—Cantharis bilineatus (Fig. 187). 28. Melyridae.—Collops nigriceps (Figs. 40, 188, 333, 478). 29. Cleridae.—Trichodes nutalli (Figs. 41, 189, 334, 479). 30. Corynetidae.—Necrobia rufipes (Figs. 42, 190, 335, 480). LYMEXYLOIDEA. 31. Lymexylidae.—Hylecoetus lugubris (Figs. 43, 191, 336, 481). 32. Micromalthidae.—Micromalthus debilis (Figs. 44, 192, 337). CUPESOIDEA. 33. Cupesidae.—Cupes concolor (Figs. 45, 193, 338, 482). MoRDELLOIDEA. 34. Cephaloidae.—Cephaloon lepturides (Figs. 46, 194, 339, 483). 35. Oedemeridae.—Nacerda melanura (Figs. 47, 195, 340, 484). 36. Mordellidae—Tomoxia bidentata (Figs. 48, 196, 341, 485). 37. Rhipiphoridae.—Macrosiagon dimidiatum (Figs. 49, 197, 342, 486). 38. Meloidae.—Epicauta marginata (Figs. 50, 198, 343, 487). 39. Eurystethidae——Eurystethus debilis (Figs. 51, 199, 344, 488). 40. Othniidae.—Othnius sp. (Figs. 52, 200, 345, 489). 41. Pythidae——Pytho planus (Figs. 53, 201, 346, 490). 42. Pyrochroidae.—Neopyrochroa flabellata (Figs. 54, 202, 347, 491). 43. Pedilidae—Macratria murina (Figs. 55, 203, 348, 492). 44, Anthicidae.—Notoxus anchora (Figs. 56, 204, 349, 493). 45. Euglenidae.—Zonantes fasciatus (Figs. 57, 205, 350, 494). ELATEROIDEA. 46. Cebrionidae.—Cebrio bicolor (Figs. 58, 206, 351, 495). 47. Plastoceridae.—Euthysanius lautus (Figs. 59, 207, 352, 496). 48. Rhipiceridae.—Sandalus niger (Figs. 60, 208, 353, 497). 49. Elateridae.—Alaus oculatus (Figs. 61, 209, 354, 498). 50. Eucnemidae.—Isorhipis ruficornis (Figs. 62, 210, 355, 499). 51. Throscidae.—Throscus chevrolati (Figs. 63, 211, 356, 500). 52. Buprestidae —Chalcophora virginiensis (Figs. 64, 212, 357, 501). DRYOPOIDEA. 53. Psephenidae.—Psephenus lecontei (Figs. 65, 213, 358, 502). 54. Dryopidae.—Helichus striatus (Figs. 66, 214, 359, 503). 55. Elmidae.—Stenelmis sinuata (Figs. 67, 215, 360, 504). 56. Heteroceridae.—Heterocerus undatus (Figs. 68, 216, 361, 505). 57. Georyssidae.—Georyssus californicus (Figs. 69, 217, 362, 506). DASCILLOIDEA. 58. Dascillidae——Eurypogon niger (Figs. 70, 218, 363, 507). 59. Eucinetidae.—Eucinetus morio (Figs. 71, 219, 364, 508). 13] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 13 60. Cyphonidae.—Cyphon ruficollis (Figs. 72, 220, 365, 509). 61. Chelonariidae.—Chelonarium errans (Figs. 73, 221, 366, 510). BYRRHOIDEA. 62. Dermestidae.—Dermestes lardarius (Figs. 74, 222, 367, 511). 63. Byrrhidae—Byrrhus americanus (Figs. 75, 223, 368, 512). 64. Nosodendridae.—Nosodendron unicolor (Figs. 76, 224, 369, 513). RHYSODOIDEA. 65. Rhysodidae.—Rhysodes americanus (Figs. 77, 225, 370, 514). » CUCUJOIDEA. 66. Ostomidae.—Tenebroides sinuatus (Figs. 78, 226, 371, 515). 67. Nitidulidae. Nitidulinae——Phenolia grossa (Figs. 79, 227, 372, 516). Cryptarchinae—Glischrochilus fasciatus (Figs. 80, 228, 373, 517). 68. Rhizophagidae.—Rhizophagus bipunctatus (Figs. 81, 229, 374, 518). 69. Monotomidae.——Phyconomus marinus (Figs. 82, 230, 375, 519). 70. Cucujidae. Cucujini—Cucujus clavipes (Figs. 83, 231, 376, 520). Hemipeplini—Hemipeplus marginipennis (Figs. 84, 232, 377, 521). 71. Erotylidae. Langurinae.—Languria mozardi (Figs. 85, 233, 378, 522). Erotylinae—Megalodacne fasciata (Figs. 86, 234, 379, 523). 72. Derodontidae.—Derodontus maculatus (Figs. 87, 235, 380, 524). 73. Cryptophagidae.—Anchicera ephippiata (Figs. 88, 236, 381, 525). 74. Byturidae.—Byturus unicolor (Figs. 89, 237, 382, 526). 75. Mycetophagidae——Mycetophagus punctatus (Figs. 90, 238, 383, 527); 76. Colydiidae. Bothriderini—Bothrideres geminatus (Figs. 91, 239, 384, 528). Cerylonini—Philothermus glabriculus (Figs. 92, 240, 385, 529). 77. Lathrideridae —Melanophthalma cavicollis (Figs. 93, 241, 386, 530). 78. Mycetaeidae—Phymaphora pulchella (Figs. 94, 242, 387, 531). 79. Endomychidae.—Endomychus biguttatus (Figs. 95, 243, 388, 532). 80. Phalacridae—Phalacrus politus (Figs. 96, 244, 389, 533). 81. Coccinellidae——Hippodamia convergens (Figs. 97, 245, 390, 534). Adalia bipunctata (Figs. 98, 246, 391, 535). TENEBRIONOIDEA. 82. Alliculidae.—Pseudocistela brevis (Figs. 99, 247, 392, 536). 83. Tenebrionidae.—Alobates pennsylvanica (Figs. 100, 248, 393, 537). Tenebrio molitor (Figs. 101,.249, 394, 538). Boros unicolor (Figs. 102, 250, 395, 539). 84. Lagriidae——Arthromacra aenea (Figs. 103, 251, 396, 540). 85. Monommidae.—Hyporphagus sp. (Figs. 104, 252, 397, 541). 86. Melandryidae.—Penthe obliquata (Figs. 105, 253, 398, 542). 87. 88. 89. 90. 91. O27: ILLINOIS BIOLOGICAL MONOGRAPHS [14 Ptinidae.—Ptinus brunneus (Figs. 106, 254, 399, 543). Anobiidae.—Sitodrepa panicea (Figs. 107, 255, 400, 544). Bostrichidae.—Bostrichus bicornis (Figs. 108, 256, 401, 545). Lyctidae.—Lyctus planicollis (Figs. 109, 257, 402, 546). Sphindidae.—Sphindus americanus (Figs. 110, 258, 403, 547). Cisidae.—Plesiocis cribrum (Figs. 111, 259, 404, 548). SCARABAEOIDEA. 93. Scarabaeidae. Aphodiinae.—Aphodius fimetarius (Figs. 112, 260, 405, 549). Melolonthinae.—Dichelonyx elongata (Figs. 113, 261, 406, 550). Rutelinae.—Pelidnota punctata (Figs. 114, 262, 407, 551). Dynastinae.—Strategus julianus (Figs. 115, 263, 408, 552). Cetoniinae.—Osmoderma eremicola (Figs. 116, 264, 409, 553). 94. Trogidae.—Trox suberosus (Figs. 117, 265, 410, 554). 95. Lucanidae.—Pseudolucanus capreolus (Figs. 118, 266, 411, 555). 96. Passalidae.—Passalus cornutus (Figs. 119, 267, 412, 413, 556). CERAMBYCOIDEA. 97. Cerambycidae. Prioninae. Parandrini—Parandra brunnea (Figs. 120, 268, 414, 557). Prionini—Derobrachus brunneus (Figs. 121, 269, 415, 558). Cerambycinae. Spondylini—Spondylis buprestoides (Figs. 122, 270, 416, 559). Clytini—Glycobius speciosus (Figs. 123, 271, 417, 560). Lamiinae.—Tetraopes tetrophthalmus (Figs. 124, 272, 418, 561). 98. Chrysomelidae. Donaciinae.—Donacia piscatrix (Figs. 125, 273, 419, 562). Orsodacninae.—Syneta ferruginea (Figs. 126, 274, 420, 563). Criocerinae.—Criocerus asparagi (Figs. 127, 275, 421, 564). Cryptocephalinae.—Cryptocephalus quadruplex (Figs. 128, 276, 422, 565). | Eumolpinae.—Chrysochus auratus (Figs. 129, 277, 423, 566). Chrysomelinae.—Leptinotarsa decemlineata (Figs. 130, 278, 424, 567). Galerucinae.—Diabrotica 12-punctata (Figs. 131, 279, 425, 568). Halticinae.—Blepharida rhois (Figs. 132, 280, 426, 569). Hispinae.—Anoplitis gracilis (Figs. 133, 281, 427, 570). Cassidinae.—Chelymorpha argus (Figs. 134, 282, 428, 571). 99. Mylabridae.—Pachymerus gleditsiae (Figs. 135, 283, 429, 572). BRENTOIDEA. 100. Brentidae.—Eupsalis minuta (Figs. 136, 284, 430, 573). CURCULIONOIDEA. 101. Belidae.—Ithycerus noveboracensis (Figs. 137, 285, 431, 574). 15] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 15 102. Platystomidae——Eurymycter fasciatus (Figs. 138, 286, 432, 575). 103. Curculionidae. Rhinomacerinae.—Rhinomacer pilosus (Figs. 139, 287, 433, 576). Rhynchitinae—Rhynchites bicolor (Figs. 140, 288, 434, 577). Attelabinae.—Attelabus analis (Figs. 141, 289, 435, 578). Otiorhynchinae.—Epicaerus imbricatus (Figs. 142, 290, 436, 579). Curculioninae.—Lixus fimbriolatus (Figs. 143, 291, 437, 580). Thecesterninae.—Thecesternus humeralis (Figs. 144, 292, 438, 581). Calendrinae——Sphenophorus aequalis (Figs. 145, 293, 439, 582). SCOLYTOIDEA. 104. Platypodidae.—Platypus flavicornis (Figs. 146, 294, 440, 583). 105. Scolytidae. Scolytinae.—Scolytus quadrispinosus (Figs. 147, 295, 441, 584). Hylesininae——Dendroctonus valens (Figs. 148, 296, 442, 585). 16 ILLINOIS BIOLOGICAL MONOGRAPHS [16 HEAD-CAPSULE There exists a distinct homogeneity in the general character of the structure of the head-capsule of Coleoptera. Its uniform strong chitiniza- tion is typical. So is the spacious area occupied by the mouth-parts, producing a relatively broad cephalic end. Especially characteristic is the wide space between the occipital foramen and the submentum. Then, there is that indescribable similarity of structure, even between groups widely separated, that can best be appreciated from a thorough knowledge of the morphology. As an illustration, there is little super- ficial resemblance between Harpalus (Figs. 5 and 153) and Phalacrus (Figs. 96 and 244), either in external or in internal morphology. Their distinct differences are merely due to two divergent lines of development. The structures of the dorsal surface of Phalacrus have become highly specialized, whereas those of Harpalus are relatively generalized. On the other hand, on the ventral surface the metatentorina has remained in a relatively primitive condition in Phalacrus, whereas in Harpalus its position is highly specialized. The internal structures of Phalacrus are rudimentary or lacking, while in Harpalus they are in a well developed primitive state. Considering the degree of generalization of each species, there can hardly be any question that Harpalus is the more generalized.’ The above comparative description simply illustrates roughly the problems of complexity of development that are encountered. The two distinctive kinds of development as shown above for Harpalus and Phalacrus, that of specialization of the dorsal surface and that of separate specialization of the ventral surface, do not in the least necessarily parallel one another in the Coleoptera. Indeed, these two lines of development are predominantly divergent. In the majority of species, the development is trending towards the obliteration of sutures and consequent consolidation of sclerites, and towards the development of a compactness of form of the sclerites that do not consolidate. The general trend towards a cephalization of migratory structures is a part of this process, too, as well as the development of a stronger chitinization of the head-capsule asa whole. The entire phenome- non appears to be for purposes of strengthening the head. Besides Phalacrus typical examples are Tenebrioides (Fig. 78), Glischrochilus (Fig. 80), Megalodacne (Fig. 86), and all the Scarabaeoidea. On the other hand these processes have lagged behind on the ventral surface in Phalacrus and others. It is true that the hypothetical type (Fig. 149) shows a marked cephalization of the submentum, with obliteration of 17} THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 17 sutures resulting from this migration. Yet the predominant condition of the heads studied shows only a certain degree of removal from the primitive type. Stronger chitinization has probably kept pace with the cephalization of the dorsal surface, as well as the growing compactness of such a structure as the submentum. But the very significant structure of the ventral surface, the metatentorina, only shows a certain degree of removal from the primitive condition in most of the heads. Developmental processes such as are discussed above can be best worked out through a comparative study of a large series of forms. In fact the determination of the homologies of some structures entering into these developmental processes, as for example the various changes in the epicranial suture, and the determination of the nature and line of development of the area between the occipital foramen and the submentum, would probably be most difficult without this comparative study. The chief value of this study lies in all probability in the determination of homologies, to the end of understanding the lines of development present. The homology existing between the various structures of the head-capsule of Coleoptera and other orders of insects, particularly the generalized orders, seems to work out satisfactorily. From such an homology the hypothetical type was constructed without much difficulty. In general appearance the head is oblong and rather flattened dorso-ventrally. Such a form is fairly characteristic of generalized insects and of the more generalized Coleoptera. The mouth may be considered as directed cephalad. Such a direction is representative of the vast majority of the heads, and for purpose of convenience, at least, the following discussion considers the head as extending cephalad. Some possible exceptions in which the head appears to be directed ventrad are found in Calopteron (Fig. 329), Macrosiagon (Fig. 342), Isorhipis (Fig. 355), Throscus (Fig. 356), Byrrhus (Fig. 368), and a few others. It should not be forgotten, however, that in primitive insects the mouth is directed ventrad, and the occipital foramen is on one side instead of at the opposite end. The line of closure of the head in the embryo is represented by the epicranial suture. The complete epicranial suture is typical of generalized insects. Where it is present in Coleoptera, this denotes a generalized condition. The primitive form of the epicranial suture is that of a deep inverted Y, with the cephalic ends of the arms near the lateral border of the labrum. The hypothetical head is represented as having a complete epicranial suture. The epicranial stem extends to a transverse line drawn through the middle of the compound eyes. Branching here the epicranial arms continue to the margin of the head cephalad of the compound eyes, A complete epicranial suture is not of general occurrence in the Coleoptera. It is practically complete in Hydrous (Fig. 13) and Hydrophilus (Fig. 14), 18 ILLINOIS BIOLOGICAL MONOGRAPHS [18 very distinct and sharply invaginated in both, particularly so in the former, and characteristic in form. Each arm reaches the margin of the head almost immediately cephalad of a compound eye, and the arms are not as generalized in position as they are in Epicauta (Fig. 50), where they are quite distinct. The only other occurrence of a complete epicranial suture is in Chelymorpha (Fig. 134). Here the arms meet the stem farther caudad than in the other genera named. The arms in this last genus are distinctly curved, as contrasted with the more or less straight arms in the above mentioned genera. The epicranial arms or some portion of them are present in all Coleop- tera, except possibly in Calopteron (Fig. 36) and Photinus (Fig. 37). One or more species of every superfamily of the Adephaga and Polyphaga, except the Elateroidea, Byrrhoidea, Rhysodoidea, and Rhynchophora, have the arms complete. In the Caraboidea they are prominent as nearly straight sutures across the head, as in Tetracha (Fig. 2), Cicindela (Fig. 3), Calosoma (Fig. 4), and Harpalus (Fig. 5). Their most generalized condi- tion in the Adephaga is found in OQmophron (Fig. 7) in which they extend from the meson at a sharp angle. Representative species of other super- families that have the arms complete are: Necrophorus (Fig. 18), Tachinus (Fig. 27), Chauliognathus (Fig. 39), Cupes (Fig. 45), Cephaloon (Fig. 46), Notoxus (Fig. 56), Heterocerus (Fig. 68), Eucinetus (Fig. 71), Myceto- phagus (Fig. 90), Tenebrio (Fig. 101), Bostrichus (Fig. 108), Aphodius (Fig. 112), and nearly all the Cerambycoidea. Species having parts of the epicranial stem preserved are not very common. In Omophron (Fig. 7), Tachinus (Fig. 27), Penthe (Fig. 105), and a number of the Cerambycoidea, parts of the cephalic end can be identified; in Omophron (Fig. 7), Phengodes (Fig. 38), Cupes (Fig. 45), Sitodrepa (Fig. 107), Blepharida (Fig. 132), and a number of the Rhynchophora, parts of the caudal end are present. Chalcophora (Fig. 64) and Tetraopes (Fig. 124) are peculiar in possessing practically all of the stem but little of the arms. The arms in Chalcophora are as short as in any other species studied. Parts of the arms are present in every degree of length from nearly meeting on the meson, as in Nosoden- dron (Fig. 76), to almost complete disappearance as in Chalcophora (Fig. 357) and Rhysodes (Fig. 370). They also show varying degrees of dis- appearance and invagination, from the deep distinct invaginations of . such forms as Dineutes (Fig. 10), Necrophorus (Fig. 18), Tachinus (Fig. 27), Heterocerus (Fig. 68), and Arthromacra (Fig. 103), to the faint or slender and shallow or not at all invaginated sutures characteristic of the Scarabaeoidea. The character of the invagination associated with the epicranial arms is not as simple as may be thought. In Harpalus (Figs. 5 and 24), the epicranial arms extend from the meson along the edge of the invagination to the pretentorinae, from which they extend to the bottom of the invagi- 19] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 19 nation, curve laterad, and continue to the margin of the head. The course of the epicranial arms can be better understood from Omophron (Fig. 7), a related genus, which has retained the cephalic portion of the epicranial stem. The line of the invagination appears to be and often is considered to be simply the clypeal suture. If a specimen of Harpalus is soaked for a long time in potassium hydroxide the invagination can be opened and the various structures in this region studied advantageously. The invagina- tion when opened (Fig. 24) will be seen to assume a deep wide wedge- shaped form, extending entirely across the dorsal surface of the head. The pretentorinae are located on the external dorsal surface just caudad of the cephalic margin of the invagination. Although the epicranial arms are not in evidence anywhere between the me: sn and the pretentorinae, it is assumed that the cephalic marginal ridge must represent them, since the pretentorinae are not only located caudad of the invagination, but the arms are quite distinct, extending from the pretentorinae to the bottom of the invagination, in which they then curve laterad and continue to the margin of the head. From a cross-section (Fig. 23) it will be seen that the pretentorium expands cephalad in characteristic form from the preten- torina along an epicranial arm to the bottom of the invagination. In Calosoma (Fig. 4) the same condition of this region is found as in Harpalus. In Omophron (Fig. 7) the epicranial arms are distinct between the preten- torinae, extending from the meson along the cephalic border of the invagi- nation. From Figure 24 it will be observed that the cephalic border of the invagination in Harpalus is along the imaginary line of the fronto-clypeal suture. This border may represent the cephalic limit of the front. The invagination, then, in Harpalus and Calosoma includes the entire front. The line of the invagination instead of being solely a part of the epicranial suture is in fact compound in nature, representing the approximation of the caudal borders of the front and postclypeus, and that part of it between the pretentorinae may be termed the “clypofrons.”’ Laterad of the pretentorinae to the margin of the head the line of the invagination is readily seen to be an approximation of a part of the vertex with the caudal border of the postclypeus and cannot be included in the clypofrons. Due to the more primitive position of the epicranial arms in Omophron the invagination in this genus contains only a part of the front, hence the line of the invagination between the pretentorinae is simple in nature. In Tachinus (Fig. 27) the epicranial stem extends distinctly into the in- vagination, the arms continuing in the same to the margin of the head. As should be expected, the pretentorinae are within the invagination. The line of the invagination in Tachinus is then of a different character from that of either Harpalus or Omophron. In Tachinus, it has nothing whatever to do with the epicranial suture nor with any other suture, being throughout the approximation of parts of the external dorsal surface of 20 ILLINOIS BIOLOGICAL MONOGRAPHS (20 the vertex and the front. It is obvious from the above discussion of three types of the invagination associated with the epicranial arms that the dorsal surface of the head-capsule in Coleoptera must be studied most carefully before a correct interpretation of the parts can be made. This is most true in the case of any invagination that may be present. The latter may not be readily observed when the head-wall is strongly and darkly chitinized, necessitating treatment of such specimens before the parts can be clearly made out. In Dermestes (Fig. 74), and perhaps others, all external trace of the line of the invagination may be lost. In such cases a true understanding of the parts can only be gained from an ex- amination of the ental surface of the head. But in specialized forms the ental indication of the invagination may also be effaced. The epicranial suture can always be located from the determination of the position of the pretentorina. The latter is always closely associated with the epicranial suture, being present either in or just off of the suture, in which case the pretentorina resembles a sort of pocket. There is usually little difficulty experienced in locating the suture. The cephalic ends of the arms are the most persistent parts of it, being present when the remainder of the suture cannot be identified. Interesting examples are found in most Rhynchophora, where the remnants of the epicranial arms are represented by short furrows located at the cephalic end of the snout. The epicranial arms are typically structures of the dorsal aspect, but with the shifting and modification of other parts of the head may be confined to the lateral aspect, as in Helichus (Fig. 359), Adalia (Fig. 391), or to the ventral aspect, as in Cybister (Fig. 157), Hydrous (Fig. 161) and Phalacrus (Fig. 244). From the preceding discussion of the epicranial suture it is seen that what appears superficially to be this suture may not be so. It is a difficult problem to understand the kind and amount of change that may have taken place. In a number of the Rhynchophora, for instance, what appears to be the epicranial stem (Figs. 146 and 147) may be only invaginations, for in these same species are lateral invagina- tions that are quite similar in form to the so-appearing epicranial stem. The epicranial stem seems to the writer to hold the strongest claims, so these invaginations are considered as such. So, in other instances, where a structure appears to be more definitely the epicranial suture than any- thing else, it is so interpreted. That part of the head-capsule not embraced by the three primary sclerites cephalad of the epicranial arms, the occiput, and the postgena, constitutes the vertex. Its extent is determined by the form and size of the three above mentioned areas. For instance, in those species with much reduced epicranial arms, as in Creophilus (Fig. 26), Adalia (Fig. 98), and Phalacrus (Fig. 96), the extent of the vertex is correspondingly in- creased. In the Rhynchophora, as represented by such species as Lixus 21) THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 21 (Fig. 143) and Sphenophorus (Fig. 145) it is very extensive, including practically all of the snout of the dorsal and lateral surfaces. The area on the lateral surfaces of the head, cephalad of the compound eyes, be- tween the latter and the epicranial suture, is the gena, a part of the vertex. The limits of the gena are not definite. The prominent ridge in many genera, dorso-mesad of each gena and antacoria, is the so called frontal ridge, that extends in the general direction from the epicranial arms to the mesal margin of the compound eyes. The frontal ridge is prominent in Harpalus (Fig. 5), Necrophorus (Fig. 18), Trichodes (Fig. 41), Neopyro- chroa (Fig. 54), Dermestes (Fig. 74), and many others. In generalized insects the occipital suture is confined to the ventral or caudal aspect, beginning near the lateral margin of the postcoila and extending around the caudal or dorsal margin of the occipital foramen. In the Coleoptera this suture arises laterad of the postcoila, extends cephalad for a considerable distance, then eurves abruptly laterad, ex- tending onto the dorsal aspect of the head, where it joins the suture of the other side of the meson. The genus Cicindela (Figs. 3, 151, and 298) possesses the most generalized condition of this suture found in the Coleop- tera. The cephalic end of the suture is modified into a ridge. This ridge is considered a later development, and is not shown in the hypothetical type. It unquestionably represents a part of the occipital suture, and can be identified in practically all the Coleoptera, as in such widely separated groups as Molamba (Fig. 168), Nacerda (Fig. 195) and Byturus (Fig. 237). The occipital suture separates the vertex from the occiput and the post- gena. Only the Caraboidea seem to possess with certainty an unmodified occipital suture. In Cicindela (Fig. 3) it is complete and nearly so in Tetracha (Figs. 2, 150, and 297), but very faint in great part. In Calo- soma (Fig. 152) the unmodified suture begins farther caudad and is more distinct. In Omophron (Fig. 302), two short, characteristically curved, lateral ridges no doubt represent remnants of the occipital suture. The ridge across the lateral aspect in Peltodytes (Fig. 303) may also represent this suture. In Cybister (Fig. 157) it is probably represented by the crescent-shaped suture on the ventral aspect. Ridges and furrows ap- pearing in the same general location in other species, such as Aleochara (Fig. 321), Throscus (Fig. 356), Cyphon (Fig. 365), and Aphodius (Fig. 405), may possibly be homologized as occipital sutures. In most cases these ridges seem to be merely to mark the limits to which the head is telescoped in the prothorax. In those species possessing an occipital suture the occiput is recognized as a distinct area. It includes the region between the occipital foramen and the occipital suture as far as the postgena, appearing as a sort of broad band across the dorsal aspect, divided by the epicranial stem and in- distinguishably fused on the lateral aspect with the postgenae. Examples 22 ILLINOIS BIOLOGICAL MONOGRAPHS [22 of a well marked occiput are present in Tetracha (Fig. 2), Cicindela (Fig. 3), Calosoma (Fig. 4), and Harpalus (Fig. 5). In Omophron (Fig. 302) the occipital suture is so short that the limits of the occiput cannot be definitely determined. In those species not possessing a recognizable unmodified portion of the occipital suture, the limits of the occiput can only be judged accordingly. Even in generalized insects the occiput is nearly always fused with the postgenae, and is so represented in the hypothetical type. There is a great similarity in the form and location of the compound eyes. The general form is oval. They are located near the middle of the lateral margin of the head. Such a form and location is given in the hypo- thetical type. There are a number of interesting variations in form from the normal type. Dineutes (Fig. 305) and Tetraopes (Fig. 124) have four complete eyes. This phenomenon is produced by a projection of a part of the vertex into the eye that in time completely separates the two halves. The line of closure between the projection and the opposite side is indicated by a distinct line—the exoculata. The beginning of such a projection is shown in Cephaloon (Fig. 46), Epicauta (Fig. 50) and many others. In Pseudocistela (Fig. 99) and Osmoderma (Fig. 116) the projection ex- tends more than half-way across the eye. In Throscus (Fig. 63) the projection nearly separates the two halves. The eyes of Peltodytes (Fig. 8), Photinus (Fig. 37) and Stenus (Fig. 22) are very large. Unusual forms of the eyes are found in Hypophagus (Fig. 104), where they are very long and narrow nearly meeting on the dorso-meson; in Cryptocephalus (Fig. 128), where they are prominent, crescent-shaped, and extend well caudad on the dorsal surface; and in Aphodius (Fig. 112), where they are relatively small and square-like. The eyes of Limulodes (Fig. 324) are transparent and almost invisible; those of Leptinus (Fig. 312) are com- pletely wanting. The oculata is present only on the inside periphery of the eye as a broad ring-like shelf. It is considered of little importance in this study. Its general size is indicated by the dotted area within the eyes of Cicindela (Fig. 298), Dineutes (Fig. 305), Passalus (Fig. 412), and a few others. In forms with divided eyes the two sides of an oculata are pressed together, forming an exoculata. The supratentorinae represent the point of attachment on the head- capsule of the supratentoria. They are not thought to be primary in- vaginations, and may probably represent no more than depressions. In the Coleoptera the supratentorinae are not prominent, as the pretentorinae and metatentorinae often are. They are situated on the dorsal surface of the vertex. Their presence is not general, occurring commonly only in the Staphylinoidea. Outside of this superfamily the supratentorinae are found only in Phyconomus (Fig. 82) and Philothermus (Fig. 92). The 23] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 23 supratentoria are usually attached to the inner membrane of the body-wall, but unless an actual mark of their presence is indicated on the external surface the supratentorinae are not considered as present. In generalized insects the latter are generally present. Their presence in the Coleoptera should indicate a primitive state. In all the Coleoptera examined, no indication of any ocelli has been observed. In generalized insects there is a ring-like sclerite surrounding the periphery of each antacoria. In Coleoptera this sclerite is present, but it is distinguished from the head-capsule by a ridge only. On most heads it is considerably reduced in size, about all that can be seen of it externally being its projection, the antacoila, upon which the scape of the antenna articulates. On the other hand, in Sandalus (Fig. 353), Derobrachus (Fig. 120), Tetraopes (Fig. 124), Leptinotarsa (Fig. 130), and Anoplitis (Fig. 133), the antennaria is quite prominent. The most generalized position of the antennaria is considered to be on the gena cephalad of the eye, notwithstanding that in generalized insects the antennariae are quite fre- quently found distinctly between the eyes. Embryology, however, shows that the antennae are postoral in origin. Furthermore, in coleop- terous larvae each antennaria is located cephalad of the ocellarae. Such a position in coleopterous adults should denote the more generalized condi- tion. The antennaria is very unstable in position. There is hardly a superfamily in which it does not appear in both the generalized position and elsewhere. In the Scarabaeoidea and Cerambycoidea, though the position of the antennaria varies within certain limits, yet it shows a char- acteristic location. In the former it is either on the lateral or ventral aspects, while in the latter it occurs only on the dorsal aspect. In no other large groups does the antennaria appear so constant in position. In Calopteron (Fig. 36) and Phengodes (Fig. 38) it is exceptionally large; in Dineutes (Fig. 305) and Alobates (Fig. 392) it is exceptionally small. The membrane attaching the antenna to the head-capsule is the antacoria. In removing the antennae the antacoria is torn, and as it plays no significant part in this study no attempt was made to represent it in every case. The antacoria varies in size depending upon the size and shape of the scape. It is indicated in a number of figures by the stippled area: Omophron (Fig. 7), Necrophorus (Fig. 313), Calopteron (Fig. 36), Phengodes (Fig. 38), and Chauliognathus (Fig. 332). The depression in the vertex, usually in the gena, within which the antennaria and antacoria are situated is the antacava. It is always pres- ent, so far as is known, and is developed into a deep socket in Dineutes (Fig. 305), Connophron (Fig. 315), Scolytus (Fig. 441), and Dendroctonus (Fig. 442). The points of invagination of the pretentoria on the head-capsule are the pretentorinae. They are always located along the epicranial suture 24 ILLINOIS BIOLOGICAL MONOGRAPHS [24 in the Coleoptera. In generalized insects and the more generalized Coleoptera, they are situated on the lateral margin of the head. They are, therefore, represented in this position on the hypothetical type. The pretentorinae have been identified in every species studied except possibly Calopteron (Fig. 36) and Photinus. In the latter they are represented by depressions caudad of the eyes. Their position along the epicranial suture varies greatly. In widely separated groups they may be primitively lo- cated, as illustrated in such diverse forms as Omophron (Fig. 7), Necroph- orus (Fig. 18), Scaphidium (Fig. 33), Chauliognathus (Fig. 39), Cepha- loon (Fig. 46), Nacerda (Fig. 47), Alaus (Fig. 61), Phyconomus (Fig. 82), and Glycobius (Fig. 123). The position of the pretentorina evidently cannot possess any important significance in every instance, yet its posi- tion may be characteristic sometimes. In the Scarabaeoidea it is never on the dorsal surface; in the Cerambycoidea it is always on the dorsal surface. In this respect, the pretentorinae and the antennariae behave similarly. As a matter of fact, they are usually associated together, but there are some striking exceptions. The antennariae of Macrosiagon (Fig. 49) are located well caudad of the cephalic margin of the eyes, while the pretentorinae are situated at the ventro-lateral margin of the head (Fig. 342). The opposite condition is found in Phenolia (Fig. 79). The antennariae in the vast majority of cases are caudad of the pretentorinae. The pretentorinae are the great landmarks of the head-capsule.. On their location the determination of the presence and position of the epi- cranial suture is often dependent, and, consequently, the homologies of large areas of the head-capsule. A case in point is that of the Rhyncho- phora, in which the pretentorinae are located near the cephalic end of the snout, on the dorso-lateral margin. The epicranial suture is reduced to the very short cephalic ends of the epicranial arms, and though we cannot, therefore, indicate with precision the cephalic limits of the vertex, its ap- proximate limits can be judged, which would show the vertex to occupy nearly all the dorsal and lateral aspects of the snout. The sclerite embraced by the epicranial arms is the front. In the hypothetical type (Fig. 1) its caudal and lateral limits are the epicranial arms. Its cephalic limit is indistinguishable, since the front is fused with the postclypeus. The approximate line of fusion is indicated by a dotted line. There is no external indication in any head of a fronto-clypeal suture. The size of the front depends upon the position and direction of the epicranial arms. In those species possessing the inverted Y type of arms, the front assumes considerable proportions, but where the arms have been forced into a more or less straight line across the head, the invagination associated with the epicranial arms includes practically the entire front. As mentioned previously, the epicranial arms extend in this manner across the head in a wide series of families. The front must hence assume this 25) THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 25 form. In just as wide a series of families, the epicranial arms are in process of disappearing. In such cases, the caudal limits of the front can only be judged approximately. In great reduction of the arms, as repre- sented by Phalacrus (Fig. 96) and Macrosiagon (Fig. 49), the vertex, the front and the postclypeus are indistinguishably fused into one area. In all species the clypeus is divided into two distinct sclerites, the postclypeus and the preclypeus. This condition is not present so far as I know in the more generalized insects such as the Orthoptera and Plecop- tera. In some Neuroptera, however, the preclypeus is a large character- istic sclerite, quite similar to what has been designated as the preclypeus in the Coleoptera. It may possibly represent the extraordinary develop- ment and differentiation of the labracoria, but its size, shape and form would militate against such an assumption. It seems much easier to believe that this area is a true sclerite, and in this discussion it will be so considered. The broad cephalic part of the area between the epicranial arms in the hypothetical type (Fig. 1) represents the postclypeus. In generalized Coleoptera it is of considerable size if the dorsal surface has retained a generalized form. The shape, form, and size of the postclypeus is cor- related with the position and extent of the epicranial arms, which has already been discussed. In highly specialized forms like the Scarabaeoidea (Figs. 114, 115, and 116), the postclypeus may be even more extensive. Among the Staphylinidae, the postclypeus may be very large in Tachinus (Fig. 27) and Aleochara (Fig. 28), and very small in Creophilus (Fig. 26). In Chalcophora (Fig. 357) the cephalic end of the vertex is located on the ventral aspect of the head, and the postclypeus is reduced to hardly more than a line. Among the Cerambycoidea the postclypeus is generally very large. In the Rhynchophora it is quite reduced in size. The caudo-lateral projection or lobe of the postclypeus is the clypealia. In Orthoptera and Plecoptera the clypealia is not separated from the re- mainder of the postclypeus. In the larvae of Corydalis it is a prominent distinct sclerite. The clypealia in the Coleoptera is often separated from the postclypeus proper by a distinct furrow or suture. It is quite loosely attached to the postclypeus in the Cicindelidae (Figs. 297 and 298), the Carabidae (Figs. 299 and 300), many of the Cerambycoidea (Figs. 419 and 424), and others. Difficulty is often experienced in removing the mandi- bles from the head without detaching the clypealia. The close resemblance between the Neuroptera and the Coleoptera in other respects would lead one to believe that this similar structure in the two orders must be ho- mologous. The presence of this furrow in the Coleoptera is wide-spread, as a glance at the figures will show. It can probably show little signifi- cance as an indication of primitiveness. It must, though, have been present in the primitive Coleoptera, and is hence shown in the hypothetical type. 26 ILLINOIS BIOLOGICAL MONOGRAPHS [26 In most of the Orthoptera a small triangular area is present, extending from the precoila to the cephalic end of the occipital suture. This sclerite is known as the mandibularia. No such area has been located in the Coleoptera. The dorsal surface of the larvae of Corydalis is very generalized. On this surface there is a prominent submembranous sclerite between the postclypeus and the labrum, the preclypeus. Such a sclerite, very similar in size, form, texture, and position, is present in Tachinus (Fig. 27), Arthromacra (Fig. 103), Trichodes (Fig. 41), and Glycobius (Fig. 123). This sclerite is considered the preclypeus. Figure 23 is a longitudinal section of the dorsal aspect of the head of Harpalus, and shows the char- acteristic position of the preclypeus. It is always present in the Coleop- tera, though often considerably reduced in size. The preclypeus is al- ways membranous except in Photinus (Fig. 37), where it is chitinized and the labrum is membranous. Besides the forms mentioned above, the preclypeus is large and prominent in Necrophorus (Fig. 18), Conno- phron (Fig. 20), Macratria (Fig. 55), Philothermus (Fig. 92), Hippedamia (Fig. 97), and many others. Very frequently the cephalic end of the postclypeus is infolded, thus carrying the preclypeus and the labrum with it. In such cases the preclypeus cannot be seen from the dorsal aspect. The preclypeus, no matter how deeply it is infolded, is, except in a few cases, sharply differentiated from the postclypeus and the labrum. In Glischrochilus (Fig. 373) and Chauliognathus (Fig. 332) the postclypeus and the labrum were in such close approximation that the preclypeus could not be observed until the two above mentioned sclerites were separated, and this was possible only after long soaking in potassium hydroxide. In most of the Rhynchephora, due to the fusion or absence of the labrum, the preclypeus could not be identified. The preclypeus, however, was prominent in Attelabus (Fig. 141), and somewhat reduced in Epicaerus (Fig. 290). The broad prominent sclerite attached to the cephalic end of the clypeus in generalized insects is the labrum. In Coleoptera possessing other generalized structures, the labrum is typically of the same general form. The labrum is shown in the hypothetical type. In position the hypothetical labrum should be, with the preclypeus, in accordance with their condition in generalized insects, on the same general level with the remainder of the dorsal surface. The generalized form and position of the labrum is present in every superfamily except the Elateroidea, Dryopoidea, Rhysodoidea, Scarabaeoidea, and the Rhynchophora, in which the postclypeus has been infolded, thus forcing the labrum onto the ventral aspect. All the superfamilies containing species with the labrum generalized, contain about as many with it in various degrees of specialization, as to form, size, texture and position. The labrum in Con- 27] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 27 nophron (Fig. 20), Photinus (Fig. 37), Othnius (Fig. 52), Chelonarium (Fig. 73), Eurymycter (Fig. 138), and others, is large and membranous. The labrum of Aphodius (Fig. 260) is large but very thin and delicate. The labrum of Scolytus (Fig. 295) and Dendroctonus (Fig. 296) is prob- ably membranous. In the latter, a significant looking slightly chitinized structure is located in the membrane within the mouth that may represent thelabrum. In Thecesternus (Fig. 292) there isa membranous area closely joined to the postclypeus that probably represents the labrum. In Eupsalis (Fig. 284), Lixus (Fig. 291), Sphenophorus (Fig. 293), and Rhynchites (Fig. 288), there is an area within the mouth, bounded by furrows, that may be the labrum. Such are particularly suggestive in view of the fact that in the same location and lying flat against the post- clypeus a very thin but a relatively large and well chitinized labrum was found in Epicaerus (Fig. 290) and Attelabus (Fig. 289). The labrum in Isorhipis (Fig. 210), Nosodendron (Fig. 224), Phyconomus (Fig. 230), and Derobrachus (Fig. 269) is considerably reduced in size. It is present in every species, except possibly the rhynchophorous genera named above, where it is always said to be wanting. The prominent opening in the caudal part of the head is known as the occipital foramen. It is generally very large, but in some species, such as Connophron (Fig. 168), Cephaloon (Fig. 194), and Macratria (Fig. 203) is reduced in dimensions, due to the constriction of the caudal end of the head. In Calopteron (Fig. 182), Photinus (Fig. 183), Alaus (Fig. 209), and Tetraopes (Fig. 272), the occipital foramen is extraordinarily large. In order to understand clearly the developmental processes that take place on the ventral surface, it is necessary to consider a sclerite, belonging to the mouth-parts, the submentum. Im generalized insects the sub- mentum is not only adjacent to but is one of the covering parts of the occipital foramen. Such a position is not found in the Coleoptera. Here, it is always located cephalad of the occipital foramen, with a distinct area between the two. In the vast majority of heads this area is very wide. It is considered as having been present in primitive forms, and is shown on the hypothetical type. The submentum in generalized insects is a large quadrangular movable plate. Many genera of Coleoptera show a similar size, form, and mobility, as in Leptinus (Fig. 165), Necrophorus (Fig. 166), Stenus (Fig. 170), Nacerda (Fig. 195), Neopyrochroa (Fig. 202), Alaus (Fig. 209), Heterocerus (Fig. 216), Cyphon (Fig. 220) and Byrrhus (Fig. 223). In these three characters, and the additional one of position in re- spect to the paracoila, which in generalized insects is normally found beneath the submentum, that of the Adephaga seems to be the most primi- tive. The innumerable sizes and forms assumed by this structure through- out the entire series of families can best be judged by glancing at the figures. It is extraordinarily large in Rhysodes (Fig. 225). 28 ILLINOIS BIOLOGICAL MONOGRAPHS [28 The invaginations on the external surface of the head-capsule of the metatentoria are the metatentorinae. In the Orthoptera the meta- tentorinae are located along the cephalo-lateral or ventro-lateral border of the occipital foramen as invaginations between the maxillariae and the postgenae. They are not in any way associated with the submentum in generalized insects or in the Coleoptera. The same relative position of the metatentorinae is maintained in the Plecoptera. In a number of Coleoptera, as in Helichus (Fig. 214), Stenelmis (Fig. 215), Heterocerus (Fig. 216), and even in-the platystomid, Eurymycter (Fig. 286), this same generalized position of the metatentorinae is found. In a number. of Coleoptera the metatentorinae are situated considerably cephalad of the occipital foramen. The question might be raised as to whether the metatentorinae that are so located could possibly be more generalized in position than those situated adjacent to the occipital foramen? In every instance in which the metatentorinae are located cephalad of the occipital foramen, a suture connects the metatentorinae with the occipital foramen. In only a few cases does the suture extend much farther cephalad than the metatentorinae. This suture in the vast majority of heads studied does not extend cephalad. It is readily seen how the meta- tentorinae might be drawn cephalad and as a result a suture be formed marking their line of migration. In such a process one would naturally not expect to find a suture located cephalad of the metatentorinae, and in the cases in which the suture does extend so it is easy to understand that the force of the cephalic pull might have been communicated to this region, producing in consequence a suture or invagination. Due to the shape of the head, it is most difficult to believe that the metatentorinae could be drawn caudad, and if they were so drawn, it would seem that in this process there would be formed a suture cephalad of the metatentorinae, marking the line of migration. In this discussion the generalized position of the metatentorinae will be considered as that of its generalized position in more primitive insects, at or near the occipital foramen. In the development of the coleopterous head the metatentorinae have shown a tendency to migrate cephalad. The cephalic migration of the metatentorinae and the ventral migration of the pretentorinae and other structures, were no doubt due to the same force, the result being a closer approximation of parts, which naturally supplied increased firmness to the head’s mechanics of operation. The Dryopoidea show the most general- ized position of the metatentorinae. Genera of this superfamily have been mentioned above. The Elateroidea probably possess the next most gen- eralized metatentorinae, such as in Sandalus (Fig. 208) and Alaus (Fig. 209). The Cucujoidea show the metatentorinae just a little removed from the occipital foramen, as in Megalodacne (Fig. 234), Anchicera (Fig. 236), Philothermus (Fig. 240), and others. In the genera of other super- 29} THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 29 families, as Nosodendron (Fig. 224), Anoplitis (Fig. 236) and Tetraopes (Fig. 272), almost the same degree of primitiveness is shown. The large superfamily Mordelloidea show the metatentorinae to have migrated to about half the distance between the occipital foramen and the submentum. This condition is fairly consistent throughout the group. In the Bostri- choidea, the Scarabaeoidea, and the Cerambycoidea, the metatentorinae show considerable variation in position. This is shown by a comparison of their position in Bostrichus (Fig. 256) and Sphindus (Fig. 258). In the families to which Tetracha (Fig. 150), Calosoma (Fig. 152), Cybister (Fig. 157), Dineutes (Fig. 158), Necrophorus (Fig. 166), and Glycobius (Fig. 271) belong, the metatentorinae have advanced very far cephalad, near to the submentum. In Photinus (Fig. 183) and Chauliognathus (Fig. 185) they are located on or quite near the paracoila. There is a narrow plate surrounding the lateral and caudal margins of the occipital foramen in some generalized insects, between which and the postgenae the metatentorinae are invaginated. This plate has disappeared in the Coleoptera. The structure connecting the head-capsule with the prothorax is called the cervix. It is normally composed of membrane, and a number of cervical sclerites. The size of the cervix depends upon the size of the occipital foramen, and the degree of mobility of the head. In the Lampy- roidea and some other forms the cervix is very large. The cervix in Rhysodes is composed of tough fibrous membrane, quite different in structure from the normal cervix. In nearly all of the Rhynchophora the cervix is heavily supported by strong tendons attached at its cephalic end. These tendons take care of the added strain on the cervix due to the elongation of the snout. There are more or less small cervical tendons appearing occasionally throughout the whole series of families studied. In Molamba (Fig. 21) the cervix is invaginated within the prothorax, doubling upon itself. The cervix in Bostrichus (Figs. 256 and 401) doubles back upon the head-capsule, which is produced into a round projection. The most prominent and persistent cervical sclerites are the pleural cervical sclerites, the cervepisternum and the cervepimeron. The former is usually the larger of the two, and articulates at its cephalic end either against an odontoidea or simply against the undifferentiated area sur- rounded by the occipital foramen. The latter usually extends in a different direction from the former, and articulates at its cephalic end with the cerve- pisternum and at its caudal end with the prothorax. In Cantharis (Fig. 187), Macratria (Fig. 348), Psephenus (Fig.358) and others, there is a single large sclerite present. In the Adephaga, in Leptinus (Fig. 312), Hypor- phagus (Fig. 397), Pseudocistela (Fig. 392), and many others, there is a single small subcircular sclerite present. Both of these types probably 30 ILLINOIS BIOLOGICAL MONOGRAPHS [30 represent the cervepisternum. Ina very large number of genera cervical sclerites are always wanting. They are poorly or not at all developed in the Cerambycoidea. None of the Rhynchophora studied possess a cervical sclerite except Eurymycter (Fig. 432), in which it is very small. The ventral cervical sclerite is the cervisternum. Hister (Fig. 181), Nacerda (Fig. 195), Cucujus (Fig. 231), and a few others, possess two small cervisterna, while Tomoxia (Fig. 196) possesses a long narrow one. The cervisternum is on the whole of infrequent occurrence. The dorsal cervical sclerite is called the cervinotum. It occurs even less frequently than the cervisternum. Hydrous (Fig. 13) possesses a subquadrangular distinctly chitinized cervinotum. In Aleochara (Fig. 28) the cervinotum is divided into two distinct lightly chitinized subtriangular sclerites. Two much larger square-like sclerites are situated caudad of these. All of the Hydrophilidae and Scarabaeidae possess setaceous caudo-lateral sclerites, which do not seem to be present in the other genera studied. Owing to the strong chitinization of the head and the close fit of the head in the prothorax, there is little need for a special process or projec- tion on the head for the articulation of the cervepisternum. Such a process is called an odontoidea. Some of the species in which it does occur are Scaphidium (Fig. 179), Encinetus (Fig. 219), Cyphon (Fig. 220), Byrrhus (Fig. 223), Nosodendron (Fig. 224), and Arthromacra (Fig. 251). The latter genus, it is interesting to note, possesses no cervepisternum. That part of the head-capsule on the caudal surface, mesad of the oc- cipital suture and ventrad of each occiput, in generalized orthopterous insects is a postgena. The occiput is considered as extending to near the middle of the dorso-ventral length of the occipital foramen, thus limiting the dorsal extent of the postgenae. The latter are widely separated from each other by the occipital foramen. The lateral parts of the large sub- mentum distinctly cover the mesal parts of the postgenae. In the Coleop- tera the occipital suture separates this region from the remainder of the head-capsule, as in generalized insects, and the occiput is also indis- tinguishably fused with the postgenae. But the postgenae, instead of being widely separated and their mesal parts being covered by the lateral parts of the submentum are directly connected by the broad area located between the occipital foramen and the submentum (Fig. 149); and the sub- mentum is attached to the mesal portion of the cephalic margin of the postgenae. This area is indistinguishably fused with and undifferentiated from the postgenae in the hypothetical and the more generalized types of ventral surface. In generalized insects the submentum is joined to the cervix by the undifferentiated part of the cervix, the cervacoria. In the cephalic migra- tion of the submentum, a part or all of the cervacoria must have been drawn in behind. The postgenae alone bordered the lateral margins of 31] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 31 the submentum and the cervacoria. A possible line of development may have been the chitinization of the cervacoria and the disappearance of the sutures separating it from the postgenae. The broad area between the occipital foramen and the submentum would in such a case be a modifica- tion of part or all of the cervacoria. It is much easier to believe, instead, that because of the membranous condition of the cervacoria, no strong resistance was offered to an approach of the mesal margins of the chitinous postgenae, which would migrate thus to serve as a firm foundational support for the submentum, as well as to strengthen the solidity of the head-capsule, as a whole. The mesal margins would in time approach so close as to press the two sides of the cervacoria into a line. Fusion of the mesal margins of the postgenae would finally take place, and the cervacoria would be divided into two parts. One part would be attached to the sub- mentum entirely separated from that portion of the cervacoria bordering the occipital foramen, and would be finally reduced to a suture. The other part of the cervacoria would remain as a portion of the cervix. Whether the mesal margins of the postgenae would approach the meson as broad surfaces, or as narrow ones and later elongate, it would be dif- ficult to state with certainty, though the latter would probably happen. In the primitive coleopterous head it is not unlikely that the head was much shorter, and that the area between the occipital foramen and the submentum was correspondingly shorter, so that there would not be the necessity for a broad fusion of the mesa] margin of the postgenae. So far as observed there has been retained in no coleopterous head any marks of the line of fusion of the postgenae. Abundant evidence is found for the conclusion that the broad area between the occipital foramen and the submentum must be a part of the postgenae. A similar condition as in the Coleoptera is present in many families of insects. In many Hymenoptera the mesal margins of the post- genae are fused between the occipital foramen and the articulation of the labium. That this is the true interpretation of this structure is shown by the fact that there is often a suture on the meson showing the line of fusion; and is further substantiated by the fact that this area bears on its ventral margin the paracoilae. In all cyclorrhaphous and orthorrhaphous Diptera the area ventrad of the occipital foramen is a continuous chitinized piece, similar to that found in the Coleoptera, and is derived from the fusion of the mesal margins of the postgenae. It may be well to add here that the expression ‘“‘cephalic migration,”’ as applied to the changed location of such a structure as the submentum, may be only relatively correct in its suggestion. Very probably the oc- cipital foramen in Coleoptera has migrated dorsad, at least it has assumed this typical position. Such a migration in itself would produce an elonga- tion of the ventral surface, with a consequent production of the broad area 32 ILLINOIS BIOLOGICAL MONOGRAPHS {32 between the occipital foramen and the submentum. Whether the force exerted on the head was directed more towards the cephalization of the submentum or towards the dorsalization of the occipital foramen it would be hard to say. The condition resulting would be in either case approxi- mately thesame. For purposes of convenience and simplicity of language, the expression “‘cephalic migration” is used in this discussion. This broad area between the occipital foramen and the submentum is sometimes designated as the gula. Usually, though, the term gula is used to indicate a sclerite, on the meson of the ventral aspect, separated from the remainder of the head-capsule by distinct subparallel sutures, the gular sutures. The term gula cannot satisfactorily be applied to both an indefinite region and a distinct sclerite. The gula is considered in the latter sense in this discussion. For the present the area between the oc- cipital foramen and the submentum will simply be designated as the mesal parts of the postgenae. The cephalic end of a postgena is usually modified into a rather flat area sloping towards the meson, upon which is situated a paracoila and a postcoila. This flat area is distinguished from the remainder of the post- gena by a distinct ridge, which usually extends in a deep curve from near the lateral margin of a postcoila to near the caudo-lateral margin of the submentum. Sometimes this ridge is directed towards the occipital fora- men, as in Leptinus (Fig. 165), Cantharis (Fig. 187), Macrosiagon (Fig. 197), Isorhipis (Fig. 210), Psephenus (Fig. 213), Helichus (Fig. 214), and others. Attention has already been called to the fact that the cephalic portion of this ridge represents the cephalic end of the occipital suture. This modified part is reduced in size or indistinguishably fused with the remainder of the head, in Photinus (Fig. 183), Eucinetus (Fig. 219), Alobates (Fig. 248), Tenebrio (Fig. 249), Hyporphagus (Fig. 252), most of the Scarabaeoidea, Sphenophorus (Fig. 293), Eupsalis (Fig. 284), and Lixus (Fig. 291). There seems to be considerable confusion as to what constitutes the gula. Some investigators consider it as simply the central portion of the ventral surface of the head-capsule. Others restrict it to the distinct sclerite appearing on the meson of the ventral surface of certain insects, including the Coleoptera. Since this sclerite is distinctive and character- istic it needs a name. The term gula is quite satisfactory to apply to it. The origin of the gula also rests in considerable confusion. Comstock and Kochi (1902) consider it the sternum of the cervical segment, and to strengthen their argument they cite the situation in Corydalis, in which they state that the sternellum of the cervical segment is retained back of the gula, and they figure it as the small quadrangular sclerite immediately caudad of the gula. They do not mention the very much larger rectangular cervical sclerite caudad of their “‘sternellum.”’ The larger sclerite is sug- 33] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 33 gestive of the sternellum, and the smaller one would then represent their “sternum.”’ It is generally stated that the gula is derived from the chitini- zation of the neck membrane or cervix. In the discussion preceding, dealing with the metatentorinae and the postgenae, I have attempted to show the impossibility of such a derivation. In many orders of insects structures on the caudal aspect of the head have been designated as the gula. My interpretation would prevent the recognition of the presence of the gula in any insects other than the Coleoptera, Neuroptera, and Trichoptera. In some Coleoptera there is no gula (Figs. 168, 177, and possibly 286), whereas in others there is a complete gula (Figs. 150, 157, 172, 185, 267, and 296). Between these extreme types there are found in the Coleop- tera all gradations of a gula in process of formation (Figs. 156, 187, 210, 245, and 257). Such a range of variation in a structure simply emphasizes the importance of a comparative study of a large series of forms. The question as to which is the more generalized condition, the presence of a complete gula or the absence of one, has been previously discussed, with the verdict in favor of the latter condition. It would then be impossible, other reasons not being considered, for the gula to be the sternum of the cervical segment. The gula is the sclerite formed by the migration of the metatentorinae from the occipital foramen towards the submentum, and must be derived from the postgenae. In this migration of the metaten- torinae sutures are produced which are known as the gular sutures. The area between the gular sutures is the gula. It is evident, then, that the presence and extent of the gula depend upon the position of the metaten- torinae and the sutures which they produce. The gula is complete in all the Adephaga except Peltodytes (Fig. 156), in the Silphidae, the Staphy- linidae, the Sphaeriidae, the first four families of the Canthroidea, and the Scarabaeidae except Pseudolucanus (Fig. 266). Isolated examples in other families of a complete gula are Scaphidium (Fig. 179), Helichus (Fig. 214), Cyphon (Fig. 220), Byrrhus (Fig. 223), and Leptinotarsa (Fig. 278). The gular sutures nearly meet in Gastrolobium (Fig. 171) and Creophilus (Fig. 172), and are entirely confluent in Necrophorus (Fig. 166), Scaphidium (Fig. 179), Hister (Fig. 181), Phengodes (Fig. 184), Chauliognathus (Fig. 185), and in all the Rhynchophora except Eurymycter (Fig. 286) and Rhinomacer (Fig. 287) in which genera the gular sutures are very widely separated. In Rhinomacer the gular sutures extend nearly half the distance to the submentum. The gula in cases of confluency of the middle portion of the gular sutures on the meson is simply invaginated. The gula is complete but extremely short in Calopteron (Fig. 182) and Photinus (Fig. 183). The-cephalic ends of the gular sutures meet on the meson near the occipital foramen in Philothermus (Fig. 240) and Anoplitis (Fig. 280). The gula is partially membranous in Nosodendron (Fig. 224), 34 ILLINOIS BIOLOGICAL MONOGRAPHS [34 Sitodrepa (Fig. 255), and Plesiocis (Fig. 259). Part of it is deeply in- vaginated transversely in Scaphidium (Fig. 179), Chauliognathus (Fig. 185), Helichus (Fig. 214), Stenelmis (Fig. 215), and others. Most of the sclerites of the head-capsule are so closely united in some Coleoptera as to appear as a single piece. Strauss-Durckheim (1828) so regarded this region in the head-capsule of the May-beetle, and named it the epicranium. Used in the sense of indicating a closely united area, the term seems satisfactory and may often prove convenient. It can then be only a relative term, including at times no more than the paired sclerites of the head, when the epicranial suture is well developed. Occasionally, the preclypeus and the labrum are closely joined to the head-capsule. In such cases, the epicranium would embrace these structures, also. The small rather concave projections at the caudo-mesal margins of the postgenae against which the maxillae articulate are the paracoilae. They are usually easily identified, as in Molamba (Fig. 169), Pytho (Fig. 201), Heterocerus (Fig. 216), and Phymaphora (Fig. 242). They are usually chitinized, but are membranous in a considerable number of genera. The paracoilae are insignificant in size in Gastrolobium (Fig. 171), all of the Elateroidea, Pseudocistela (Fig. 247), and Tenebrio (Fig. 249). In generalized insects the paracoilae are situated beneath the submentum. They are found in a similar position in the Adephaga (Figs. 150, 152, 154, 157, and 158), in Hydrous (Fig. 161), and a few others. They are also always located on the postgenae in generalized insects. This position is of great importance in determining the identity of the postgenae in special- ized insects. At the cephalic end of a postgena is always found a distinct crescent- shaped acetabulum—the postcoila, against which the postartis of the mandible articulates. Throughout the genera the postcoilae exhibit some degree of difference in exact position upon the postgenae, in size, and in degree of shallowness. Their form and position are indicated in Calosoma (Fig. 152), Sphaerius (Fig. 178), Notoxus (Fig. 204), and Dero- brachus (Fig. 269). In generalized insects the postcoilae are also always located on the postgenae, and their position is of equal importance with that of the paracoilae in determining the identity of the postgenae. The rounded condyle on the ventral surface of each clypealia, against which the preartis of the mandible articulates is the precoila. It is usually crescent-shaped, but sometimes, as in Peltodytes (Fig. 156), Cybister (Fig. 157), Creophilus (Fig. 172), Endomychus (Fig. 243), Dichelonyx (Fig. 261), and others, the form is spherical. The precoilae are large in Macrosiagon (Fig. 197), Epicauta (Fig. 198), Isorhipis (Fig. 210), Chauliog- nathus (Fig. 185), Bostrichus (Fig. 256), and others, and small in Dineutes (Fig. 158), Photinus (Fig. 183), Helichus (Fig. 214), Derodontus (Fig. 235), and particularly so in Psephenus (Fig. 213). The precoilae can 35] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 35 readily be recognized by their characteristic form. Since they are always located on the caudo-lateral lobe of the postclypeus, or the clypealia of certain insects, they are a great aid in determining the limits of the post- clypeus. The endoskeleton of the head is known as the tentorium. It is com- posed of two anterior and two posterior areas or projections, and their various modifications. The anterior arms arise from the pretentorinae, and are known as the pretentoria. The posterior arms arise from the metatentorinae, and are known as the metatentoria. In generalized in- sects one end of the pretentorium expands along and is continuous with the epicranial suture. Each extends in a caudo-mesal direction, and narrows for a short distance, then expands along its mesal margin until a fusion is formed with the pretentorium of the other side, producing the cephalic bridge, or laminatentorium. The pretentoria separate and then fuse again farther caudad with each metatentorium. The metatentoria ex- tend cephalo-mesad a very short distance, their mesal margins expand and completely fuse on the meson, producing the caudal bridge or corpo- tentorium. The fusion of the pretentoria and the metatentoria is sup- posed to take place along the cephalic margin of the corpotentorium. The dorsal projections arising from the lateral margins of the pretentoria and extending toward and attached to the dorsal wall of the head, are the supratentoria. The ring-like plate surrounding the inside periphery of the occipital foramen is indistinguishably fused with and is a part of the metatentoria. The tentoria, as a whole, are distinctly chitinized and well developed. The typical condition of the tentorium in generalized insects is practically duplicated among the Coleoptera. The hypothetical type (Fig. 443) has been constructed with this similarity in mind. The greatest difficulty experienced was in deciding upon the primitive type of lamina- tentorium, whether it should be represented as complete or incomplete, that is, whether the two sides of the laminatentorium fuse on the meson or not. Many Coleoptera that in other respects are quite generalized do not show a complete laminatentorium, as Tetracha (Fig. 444), Omophron (Fig. 449), Dineutes (Fig. 452), Leptinus (Fig. 459), Tachinus (Fig. 460), and Stenelmis (Fig. 504). The hypothetical laminatentorium is repre- sented as nearly meeting on the meson. At least, such a condition is thought to be not far removed from that which actually existed in the primitive Coleoptera. Limulodes (Fig. 469), Eurystethus (Fig. 488), Pytho (Fig. 490), Philothermus (Fig. 529), Melanophthalmus (Fig. 530), Hyporphagus (Fig. 541), Sphindus (Fig. 547), and others, possess practi- cally no trace of a laminatentorium, but well developed supratentoria. The atter are fairly well developed in Photinus (Fig. 475), Collops (Fig. 478), and Alaus (Fig. 498), but there is neither a laminatentorium nor a corpo- entorium present. There is no trace of any one of the three above 36 ILLINOIS BIOLOGICAL MONOGRAPHS (36 mentioned structures in Isorhipis (Fig. 499) and Throscus (Fig. 500). Phal- acrus (Fig. 533) and Eurymycter (Fig. 575) possess only the rudiments of the pretentoria and metatentoria. The tentoria of the Cerambycoidea (Figs. 557, 560 and 566) are very delicate and membranous. The preten- toria, the metatentoria, and the corpotentorium are always complete, while the laminatentorium.and supratentoria are always either rudimentary or absent except in Pachymerus (Fig. 572) in which the supretentoria are present. Other genera showing completely membranous tentoria are numerous. Among these are Cupes (Fig. 482), Eurystethus (Fig. 488), Rhysodes (Fig. 514), Languria (Fig. 522), and Pseudocistela (Fig. 536). A generalized condition of the pretentorium, characterized by a strong chitinization as a whole, and possessing a broad flaring cephalic end, is found in the Adephaga (Figs. 449 and 451), Leptinus (Fig. 459), Necro- phorus (Fig. 460), the Staphylinidae (Figs. 465 and 467), Georyssus (Fig. 506), Eucinetus (Fig. 508), Dermestes (Fig. 511), and Derodontus (Fig. 524). There are all degrees of gradation present from the most generalized pretentoria to those very delicate membranous ones represented by such forms as Heterocerus (Fig. 505), Endomychus (Fig. 532), Pseudocistela (Fig. 536), Hyporphagus (Fig. 541), the majority of the Cerambycoidea, and the Rhynchophora. A very prevalent type, possessing a distinctly chitinized cephalic end and a membranous caudal portion sharply sepa- rated from the former, is represented in Epicauta (Fig. 487), Pytho (Fig. 490), Chalcophora (Fig. 501), Alobates (Fig. 536), Bostrichus (Fig. 545), Diabrotica (Fig. 568), Dendroctonus (Fig. 585) and most of the Scara- baeoidea. Rudimentary pretentoria are found in a number of genera, as Calopteron (Fig. 474), Tenebroides (Fig. 515), Phalacrus (Fig. 533), and perhaps all of the Rhynchophora, except Dendroctonus. The pre- tentoria of the Rhynchophora are for the most part very delicate and fragile. The difficulty of making a dissection showing the pretentoria intact is intensified by the close packing within the snout of the greatly developed tendons of the mouth-parts and the strongly chitinized pharynx. In no instance, except in Dendroctonus was a pretentorium preserved intact. In Scolytus (Fig. 584), the pretentorium is evidently rudimentary, but in none of the other genera is there a clear indication of such being the case, owing to the presence of frayed ends, suggesting that not all of the pretentorium has been seen. The presence in the Rhynchophora (Figs. 433, 435, 437, 439 and 441) of a suture in the right position for an epi- cranial suture, an invagination within the suture that suggests the preten- torina, and a projection arising from the invagination, all furnish evidence that this projection is probably the cephalic portion of the pretentorium. The pretentorium of Passalus (Fig. 413) is extraordinarily developed. The cephalic part extends as a slender bar dorso-caudad, nearly half way to the occipital foramen, then bends suddenly and extends as a huge 37] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 37 straight arm toward the corpotentorium. The tremendous development of the caudal part is due to the need of a strong support for the dorsal surface, which bears a prominent horn used in fighting. The form and size of the metatentorium is quite decidedly indicated by the position of the metatentorinae. Those genera possessing primitive metatentorinae are very apt to possess the primitive type of metaten- torium, one that is short and simple, as Limulodes (Fig. 469), Sphaerius (Fig. 470), Anchicera (Fig. 535), Philothermus (Fig. 529), Melanoph- thalmus (Fig. 530), and Sphindus (Fig. 547). It is significant to note that all of these genera are very small in size. The cephalic migration of the metatentorinae is due to a similar movement of the metatentoria. In those genera in which the metatentorinae have migrated from their primi- tive position near the occipital foramen, the metatentoria are found more or less deeply invaginated along the gular sutures, the sutures being the products of these invaginations. In most genera the metatentoria advance but little or not at all farther cephalad than the metatentorinae, but there are some exceptions, in which the metatentoria taper gradually, as in Helichus (Fig. 503), Cyphon (Fig. 509), Lyctus (Fig. 546), and all of the Scarabaeoidea, except Pseudolucanus (Fig. 555). In those genera in. which the gular sutures are confluent on the meson, the gula itself is simply | invaginated, becoming a part of the metatentorium. The same type of development has taken place in Necrophorus (Fig. 460), Scaphidium (Fig. 471), Hister (Fig. 473), Phengodes (Fig. 470), Chauliognathus (Fig. 477), and Georyssus (Fig. 506), as in the Rhynchophora. In Necrophorus, Phengodes, Chauliognathus, Eupsalis (Fig. 573) and Thecesternus (Fig. 581), the line of fusion of the invaginations of the two sides has disappeared. In Chauliognathus the invagination is greatly reduced, and in Phengodes nothing remains but a mere line. These two latter genera seem to show a greater specialization of the gular region than any other genera studied. A correspondingly deeper invagination of the ring-like plate surrounding the inside periphery of the occipital foramen has occurred with that of the gula. The whole phenomenon appears to be due to an especially strong cephalic pull on the metatentoria. This can be readily understood in the case of the Rhynchophora, in which the elongation of the snout would encourage this result. A second force may play a part here, that of the narrowing of the snout, which might assist in the enfoldment of the gula. A large number of genera, scattered throughout the series of families, possess prominent projections along the mesal margins of the metatentoria, caudad of the corpotentorium, as those of Cybister (Fig. 451), Necrobia (Fig. 480), Glischrochilus (Fig. 517), Phyconomus (Fig. 519), and Boros (Fig. 539). Some of these projections have distinct tendons attached to them, as in Scaphidium (Fig. 471), Parandra (Fig. 557), Derobrachus (Fig. 558), Donacia (Fig. 562), and Criocerus (Fig. 564). Prominent 38 ILLINOIS BIOLOGICAL MONOGRAPHS (38 lateral projections are present in Lyctus (Fig. 546), Osmoderma (Fig. 553), Parandra, Glycobius (Fig. 560), Rhynchites (Fig. 577), Epicaerus (Fig. 579), and Thecesternus (Fig. 581). Passalus (Fig. 556) is peculiar in the possession of a large well chitinized secondary bridge arising from the mesal margin of the metatentoria. Owing to the simplicity of form of a structure like the corpotentorium, but little change is indicated in it through most of the genera. The hypo- thetical type shows this structure to be a rather narrow simple band (Fig. 443). Such is fairly characteristic of the vast majority of forms. The corpotentorium is sometimes very broad, as in Ptinus (Fig. 543), Bostrichus (Fig. 545), Parandra (Fig. 557), Derobrachus (Fig. 558), Glycobius (Fig. 560), and Eupsalis (Fig: 573). In contrast are many that are quite slender and arched, as Dineutes (Fig. 452), Stenus (Fig. 463), Hister (Fig. 473), Georyssus (Fig. 506), and Mycetophagus (Fig. 527). The form of these latter has evidently resulted from the narrowing of the space between the metatentoria. An exceptionally large number of genera have only a rudimentary corpotentorium, or none at all, as in all of the Lampyroidea except Trichodes (Fig. 479) and Necrobia (Fig. 480), Epicauta (Fig. 487), Macrosiagon (Fig. 486), all of the Elateroidea, Psephenus (Fig. 502), Rhysodes (Fig. 514), Phalacrus (Fig. 533), Hippodamia (Fig. 534), and Ar- thromacra (Fig. 540). The reasons for the loss of the corpotentorium are not always evident, though in most cases, either the arms of the tentoria have expanded and approximately met on the meson, as in Rhysodes and Plesiocis (Fig. 548), or the arms are directed towards the meson and meet there, as in Connophron (Fig. 462) and all of the Elateroidea, or the pharynx rests snugly between the tentorial arms, as is so perfectly found in Chauliognathus (Fig. 477), where the pharynx is wedged so tightly between them that the whole seems like one piece, all of which conditions supply firmness to the tentorial arms and obviate the necessity for a corpo- tentorium. Of the Rhynchophora, Eurymycter (Fig. 575), Epicaerus (Fig. 579), Platypus (Fig. 583) and Lixus (Fig. 580) possess no corpoten- torium. Scolytus (Fig. 584) possesses a very rudimentary one. The dis- appearance of the corpotentorium can best be explained in the case of the Rhynchophora by the fusion of the metatentoria into one solid plate that needs no added support. The corpotentorium of most of the Ceramby- coidea is a delicate membranous structure. A common modification of the corpotenterium is the mesal projections on its cephalic border, as in Tachinus (Fig. 460), Cephaloon (Fig. 483), Tomoxia (Fig. 485), Phenolia (Fig. 510), and Philothermus (Fig. 529). A structure of the tentorium that shows perhaps a greater variability in form than any other is the laminatentorium, which appears in a great array of shapes and sizes, from the forming of a perfect and broad bridge to total disappearance. When the two sides of the laminatentorium meet 39] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 39 on the meson, the mesal margins of the laminatentorium very frequently are bent ventrad, producing a projection. Examples of this development are seen in Calosoma (Fig. 446), Cybister (Fig. 451), Necrophorus (Fig. 460), Aleochara (Fig. 467), Heterocerus (Fig. 505), Dermestes (Fig. 511), and Endomychus (Fig. 532). Genera that show the laminatentorium as hardly more than touching on the meson are Peltodytes (Fig. 450), Scaph- idium (Fig. 471), Neopyrochroa (Fig. 481), Notoxus (Fig. 493), Psephenus (Fig. 502), Cucujus (Fig. 520), Penthe (Fig. 542), and most of the Scara- baeidae. The reduction of the laminatentorium takes place so gradually that it is hard to tell when it has completely disappeared. There seems to be no indication of it in Limulodes (Fig. 469), Collops (Fig. 478), Pseudo- cistela (Fig. 536), Hyporphagus (Fig. 541), Sphindus (Fig. 547), and others. In Tomoxia (Fig. 485), Pytho (Fig. 490), Alaus (Fig. 498), Tharops (Fig. 499), Throscus (Fig. 500), and others, there is no laminatentorium. The pretentorial arms curve towards the meson and serve a similar purpose. The laminatentorium of Tachinus (Fig. 460) and Epicauta (Fig. 487) is in the form of a lobe. That of Psephenus (Fig. 502), Dichelonyx (Fig. 550), and Pelidnota (Fig. 551), possesses two long sharp cephalic projections. Arising from the dorsal surface of each pretentorium cephalad of the laminatentorium and usually extending towards the dorsal surface of the head is a projection of variable form, the supratentorium. Its generalized condition would show a rather distinctly chitinized structure, with an expanded ventral end that gradually narrows, then expands flat-like against the ental surface of the head-wall. This kind of structure is found in a very large number of genera, as all of the Adephaga except Peltodytes (Fig. 450), the Hydrophilidae, Leptinus (Fig. 459), all of the Staphylinoidea except Aleochara (Fig. 467), and Hister (Fig. 473), Pytho (Fig. 490), Nosodendron (Fig. 513), Languria (Fig. 522), Megalodacne (Fig. 523), Derobrachus (Fig. 558), and others. The supratentorium is a surprisingly persistent structure considering the large number of genera that possess it in a more or less rudimentary state. The broken ends of the tentoria of Eupsalis (Fig. 573), Lixus (Fig. 580), and Sphenophorus (Fig. 582), are expanded, which expansion may include a part of the supratentoria. This seems reasonable to believe when a rudimentary one is evidently present in Rhynchites (Fig. 577) and Attelabus (Fig. 578). Sphenophorus is peculiar in having the lateral margins of the tentoria fused to the oculata. The head-capsule of this genus is suddenly constricted at this point, which probably placed the tentorium and head-wall in contact, a fusion finally resulting. The supratentoria of Cucujus (Fig. 520) and Passalus (Fig. ~.556) are stout structures, but extremely short. In the former, this condi- tion is due to the flatness of the head, in the latter, to the unusually close proximity of a part of the pretentoria to the dorsal surface. 40 ILLINOIS BIOLOGICAL MONOGRAPHS [40 SOME PHYLOGENETIC CONSIDERATIONS With the hypothetical type of coleopterous head in mind, it is possible to note the lines of development that have taken place within the various groups. Structures have developed away from the primitive condition with varying degrees of rapidity, and sometimes in different directions. It is difficult from this study to decide on the amount of importance to attach to the change that may take place in a particular structure, and to average the degree of primitiveness as a whole of the development of the structures characteristic of a group, and to indicate with precision the place in the primitive scale of each group. As previously mentioned, owing to the wide field covered in this investigation it was impossible to find time to study a large representation of genera within each family. Such a study should help one considerably in reaching clearer conclusions as to the arrangement of the genera in the primitive scale. Using this study as a basis, it is quite possible, however, to discuss the relative importance of the structural changes exhibited by the different groups, and to suggest possible inconsistencies in the present arrangement of certain genera. Statements made in the following discussion are based only on this study. The characteristic possession by the Adephaga (Figs. 2-10, 23-24, 150-158, 297-305, 444-452) of the occipital suture, of complete epicranial arms, of a generalized position of the antennariae and of the pretentorinae, of a generalized form of labrum, and of tentorium, would force such families as the Cicindelidae, Carabidae, Amphizoidae and Omophronidae into a primitive place in the phylogenetic scale, in spite of their specialized ventral surface. No other large group shows as many primitive characters. The genera of the above mentioned families show a great similarity in all their structures and must be closely related. Of these families Omophronidae possibly possesses the most generalized dorsal surface, though the occipital suture in Omophron is not nearly complete, and does not show on this surface. Omophron can hardly hold an intermediate position between the Carabidae and the Haliplidae, for the latter family, as represented by Peltodytes, shows little similarity with any other family of the Adephaga. The form of the head is distinctly specialized, being globular, with enor- mous eyes, and the mouth-parts and the very small labrum are directed distinctly ventrad. The occipital suture is probably lacking, the epicranial suture is shorter than in any other genus of the Adephaga. On the ven- tral surface, the metatentorinae extend only half-way between the oc- 41] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 41 cipital foramen and the submentum, and the gular sutures extend no farther cephalad, whereas in all the other genera of the Adephaga the meta- tentorinae are close to the submentum and complete gular sutures are present. Finally, the tentorium of Peltodytes is not so well developed, and the supratentoria are small and do not reach the ental surface of the head-wall. In all other genera of the Adephaga the tentorium is large and strongly chitinized in all its parts. The Dytiscidae and Gyrinidae are very similar fundamentally, and differ from other adephagous families in the position on the ventral aspect of such structures as the antennariae and the pretentorinae, and by a rudimentary or absent occipital suture. The instability of the epicranial suture is well illustrated by the case of the two closely related genera, Dytiscus and Cybister, the former possessing complete, distinct arms, and a considerable part of the caudal end of the stem, the latter incomplete and rather indistinct arms and no part of the stem. The Dytiscidae and the Gyrinidae are undoubtedly more special- ized than the first four families of the Adephaga. The Hydrophiloidea (Figs. 11-14, 159-166, 306-309, 453-456) show by the form and texture of the heads of Hydrous and Hydrophielus that they are quite similar to those of the Dytiscidae and Gyrinidae, being broad and short, and strongly chitinized. The antennariae and preten- torinae of these two species have migrated ventrad, as in the other two families. The metatentorinae, the gula, and the tentorium are also al- most identical in form and condition. These species are evidently very closely related to the Dytiscidae and Gyrinidae. Hydraena is not so simi- lar, the dorsal surface of its head being more like that of the typical Carab- idae in shape and position of the parts. The gular sutures are short, as in Peltodytes. The head of Hydroscapha, its shape, the course of the epicranial arms, position of pretentorinae and antennariae, is distinctly like that of Omophron. The genera of the Silphoidea (Figs. 15-21, 163-169, 310-316, 457-462) show many inconsistencies. The dorsal and ventral surfaces and the endo- skeleton of no two genera are nearly alike. Necrophorus possesses the most generalized dorsal surface, which is very like that of the first four families of the Adephaga; Clambus, perhaps the most specialized, being distinctly consolidated. On the other hand, Necrophorus possesses the most specialized ventral surface present in this superfamily. The gular sutures are complete, and for more than half their extent meet on the meson. In contrast, there are practically no gular sutures in Connophron, a scyd- maenid, and Molamba, a corylophid. No greater extremes of this surface can be found within the limits of any other superfamily. The tentorium exhibits just as great extremes in development. That of Leptinus is quite generalized; that of Necrophorus well developed but specialized, owing to the invagination of the gula; that of Connophron with no corpotentorium 42 ILLINOIS BIOLOGICAL MONOGRAPHS [42 nor laminatentorium and rudimentary supratentorinae; that of Molamba the most rudimentary tentorium of any genus included within this study. No clearer illustration of the difficulties of indicating relationship can be shown than that exhibited by the families of the Silphoidea. A study of the Staphylinoidea (Figs. 22, 25-35, 170-181, 317-328, 463- 473) shows that the various genera of the Staphylinidae have considerable homogeneity. Tachinus departs the most from the characteristic condi- tion, in possessing a much more generalized dorsal surface than the other members of this family. The Staphylinidae possess a tentorium and a ventral surface similar on the whole to that of the Adephaga and the Hydrophiloidea. Tachinus, through the added similarity of its dorsal surface, would seem to bear a particularly close relationship to these groups. The Sphaeriidae, as represented by Sphaerius, and the Ptilidae, as represented by Limulodes, possess a primitive condition of the metaten- torinae, while Scaphidium and Hister possess confluent gular sutures. The Pselaphidae, as represented by Pilopius, and the Clavigeridae, as represented by Fustiger, in form of head and character of the ventral surface and tentorium show a close relationship to Connophron. The irregu- larities of structure displayed by the families of this group are nearly as great as those displayed by the families of the Silphoidea. Both of these superfamilies probably need considerable revising. All of the genera of the Cantharoidea (Figs. 36-42, 182-190, 329-335, 474-480) possess complete epicranial arms and dorsal portion of the anten- nariae, and lack of corpotentorium, except the Cleridae and the Coryne- tidae, represented by Trichodes and Necrobia respectively. All possess a complete gula except the latter genera and Collops, the representative of the Melyridae. This superfamily can be divided into three subgroups. One group will include the Lycidae and Lampyridae, characterized by a globular head, short broad gula, and absence of the pretentorinae. A second group will include the Phengodidae and the Cantharidae, char- acterized by a longer and flatter head and longer gula. The third group will include the Cleridae and the Corynetidae, possessing short incomplete arms, incomplete gular sutures, and a well developed corpotentorium. Collops does not seem to fit in very well anywhere, though this genus, through the form of its dorsal surface and tentorium may possibly lean towards the second group. Cantharis, of the second group, is peculiar in possessing a normal gula, whereas in the other forms the gula is rudimen- tary, though in all other respects this genus is like the other members of this group. The first and second groups are no doubt closely related. The latter is probably the more generalized, possessing a dorsal surface resem- bling to a marked extent the dorsal surface of the Carabidae. The gula, in so far as it is complete, also resembles the condition of this structure in the families of the Adephaga, and particularly in Necrophorus, of the 43] THE HEAD-CAPSULE OF COLEOPTERA—STICKN EY 43 Silphoidea. It has, however, developed much farther, even, than in Necrophorus, being not only invaginated, but reduced to a more or less rudimentary state. The first group probably evolved from the second by the change in the shape of the head, due to the enormous development of the compound eyes and the loss of much of the gular region, which has probably fused with the cervix. Parallel with these changes, the preten- toria shifted their position so that they could better support the globular head, and came to assume the direction ordinarily assumed by the supra- tentoria of other genera. The third group would appear to be more closely related to the Mordelloidea than to this superfamily. The condi- tion of the epicranial suture, the position of the antennariae, preten- torinae, and metatentorinae, the degree of development of the gula and tentorium, would all favor this assumption. The representatives of the Lymexyloidea (Figs. 43-44, 191-192, 336- 337, 481), two families of this group, are not very similar. Hylecoetus has a head that is fairly compact, directed a little ventrad, the cervix possessing a cervepisternum, and a well developed tentorium. The head of Micromalthus is more compact than that of Hylecoetus, directed cephalad, there is no sclerite in the cervix, and the tentorium is rudi- mentary. As the superfamily stands, both could be placed in the Cu- cujoidea. The representative of the Cupesoidea (Figs. 45, 193, 338, 482) studied does not show any particular peculiarities of structure of the head that would entitle it to be placed in a separate superfamily. It can be very readily included with the Mordelloidea, for approximately the same reasons as the Cleridae and Corynetidae. The genera of the Mordelloidea (Figs. 46-57, 194-205, 339-350, 483- 494) show considerable homogeneity. Most of them possess heads that are elongate, with a generalized dorsal surface and a large postclypeus and labrum, both on the same general level with the rest of the dorsal surface. The epicranial suture, however, shows considerable instability, sometimes showing complete arms and stem, as in Epicauta, while in others the epi- cranial suture may be extremely reduced, as in Macrosiagon. If these two genera are at all related, the condition of the epicranial suture can hardly throw any light on the degree of relationship. On the other hand, the metatentorinae are stable in position, and are located almost uniformly about half-way between the occipital foramen and the sub- mentum. Another characteristic feature is the fact that most of the genera possess heads that are distinctly constricted at their caudal ends to form a neck. The Oedemeridae, the Cephaloidae, the Pyrochroidae, the Pedilidae, the Anthicidae, and possibly the Cupesidae and Meloidae, seem particularly closely related, through the possession of similarly shaped heads, whose caudal ends are distinctly constricted, of a generalized dorsal 44 ILLINOIS BIOLOGICAL MONOGRAPHS [44 surface, of compound eyes that are usually more or less emarginated, of a ventral surface whose structures are practically in a similar condition, and of a tentorium that is alike throughout, with the exception of the Meloidae, in which the corpotentorium is absent. Though the dorsal surface of the Mordelloidea resembles to a considerable extent that of such families as the Carabidae and Cantharidae, yet this surface differs so widely in closely related groups that we can hardly place too much impor- tance on the resemblance here. What seems to be far more important is the totally different condition of the ventral surfaces in the Mordelloidea and the Carabidae, for instance. In the former the gular sutures and the metatentorinae extend uniformly half way between the occipital foramen and the submentum; in the Carabidae the gular sutures extend the whole distance between these parts and the metatentorinae, nearly to the sub- mentum. The Mordelloidea and such groups as the Adephaga and Hydrophiloidea do not appear to be nearly related. The members of the Elateroidea are on the whole (Figs. 58-64, 206— 212, 351-357, 495-501) homogeneous with the exception of the Bu- prestidae. The pretentorinae and the antennariae are located on the dorsal surface, and the epicranial arms extend no farther caudad than the pre- tentorinae. On the ventral aspect, the metatentorinae extend but little cephalad of the occipital foramen, and the gular sutures no farther. The corpotentorium is lacking in all except Cebrio and Euthysanius. In the Buprestidae, on the other hand, the pretentorinae and antennariae have migrated distinctly ventrad, and are not visible at all from the dorsal surface. The gular sutures extend the whole distance between the oc- cipital foramen and the submentum, and there is a distinct corpotentorium. Considering these points, the Buprestidae are hardly closely related to the rest of the Elateroidea. With the exception of the Georyssidae, the members of the Diyopbided (Figs. 65-69, 213-217, 358-362, 502-506) appear to be fairly homogeneous. The chief characteristics are very prominent widely separated metaten- torinae, located very near the occipital foramen, and a very broad sub- mentum. The ventral surface of the Georyssidae, as represented by Georyssus, is totally different. In this family the gular sutures extend nearly to the submentum, and are confluent through practically their entire extent. The metatentorinae cannot be definitely located. Georys- sus would appear to be related to Hister, both through the condition of the gula, of the tentorium, and of the dorsal surface. The general ap- pearance of the ventral surface in the Dryopoidea is much like that of the Elateroidea, and in other characteristics they are not unlike. These two superfamilies are probably related. The representatives of the four families of the Dascilloidea (Figs. 70-73, 218-221, 363-366, 507-510) studied are similar in structure. There 45] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 45 are no outstanding features that would warrant placing them in a separate superfamily. They are negative enough in their characteristics to fit in, perhaps, in a number of other superfamilies, such as the Mordelloidea, Cucujoidea, and Tenebrionoidea. The representatives of the three families of the Byrrhoidea (Figs. 74-76, 222-224, 367-369, 511-513), the Dermestidae and the Byrrhidae studied, Dermestes and Byrrhus, do not seem to differ decidedly from one another, but the Nosodendronidae, represented by Nosodendron, may fit in better in some other group, such as the Dryopoidea. They resemble the members of this latter group in the position of the meta- tentorinae and in the form of the submentum. In Nosodendron, the metatentorinae are almost adjacent to the occipital foramen, with a mem- branous area included between them. That part of the metatentorium surrounding the periphery of the occipital foramen projects deep into the head. The supratentoria are well developed. None of these charac- teristics are possessed by the other two genera studied. The representative of the single family of this superfamily (Figs. 77, 225, 370, 514) studied, Rhysodes, shows distinct peculiarities in the structure of its head, such as an extremely thick chitinous head-wall, a fibrous condition of the cervix, an arrow-shaped head, enormously de- veloped submentum, and very small mouth-parts. Its relationships are not at all clear. The members of the Cucujoidea (Figs. 78-98, 226-246, 371-391, 515-535) show on the whole a short broad head-capsule, a distinct ventral migration of the antennariae and pretentorinae, the degeneration of the epicranial arms, and a slight migration of the metatentorinae from the occipital foramen. There is some variation in the dorsal aspect. The genera belonging to the Mycetophagidae, the Mycetaeidae, the Melan- ophthalmidae, the Endomychidae, and perhaps those of a few other families, possess dorsal surfaces that strongly resemble the dorsal surface of the Mordelloidea. In Derodontus and Philothermus, a colydiid, the anten- nariae and the pretentorinae are both on the dorsal aspect, located con- siderably caudad. The ventral aspect of all the members of the group, however, is strikingly similar. The tentorium is fairly uniform through- out the group except in Tenebroides and Phalacrus, in which the preten- torium has distinctly degenerated, due probably to the heavy chitiniza- tion of the head-wall. In the shape of the head and the condition of the metatentorinae and the gular sutures, the Cucujoidea show a similarity to the Mordelloidea, and to the superfamily Tenebrionoidea. There are no particular characteristics of the head-capsule that would separate the Tenebroidea (Figs. 99-111, 247-259, 392-404, 536-548) from the typical Mordelloidea. For instance, the dorsal and ventral surfaces and the endoskeleton of Arthromacra, Pseudocistela, and Penthe, 46 ILLINOIS BIOLOGICAL MONOGRAPHS [46 are almost exactly like these parts of such genera of the Mordelloidea as Epicauta, Cephaloon, and Macratria. The corpotentorium of Arthro- macra and Epicauta is, however, lacking. The structure of the various parts of the head-capsule of the representatives of the Bostrichidae varies considerably. The epicranial arms are complete in Bostrichus, Lyctus, Plesiocis, and Sphindus. With the exception of Sphindus these families show a distinct ventral migration of the antennariae and pretentorinae. In contrast, Ptinus and Sitodrepa do not possess complete arms, and the antennariae and pretentorinae are located more dorsad, markedly so in the former. On the ventral surface, there is considerable variation in the position of the metatentorinae. The tentorium also varies a great deal. This is probably not a very homogeneous group. Sphindus seems to be structurally more similar to Sphaerius than any other genus studied. The Scarabaeoidea (Figs. 112-119, 260-267, 405-413, 549-556) is a very homogeneous group, characterized by a heavy chitinization of the head-wall, degeneration of the epicranial suture, ventral migration of the antennariae and the pretentorinae, and a complete gula, except in Pseudo- lucanus, in which the gular sutures extend no more than half the distance between the occipital foramen and the submentum. In the development of the ventral surface and perhaps the tentorium, the Scarabaeoidea should be classed with the Adephaga and related groups. The Cerambycoidea (Figs. 120-135, 268-283, 414-429, 562-572) is also a very homogeneous group, characterized by a weak chitinization of the head-wall, a distinct dorsal position of the antennariae and the pre- tentorinae, and a more or less well developed epicranial suture. The gular sutures are generally short. The tentorium is delicate and mem- branous throughout. The members of the Rhynchophora (Figs. 136-148, 284-296, 430-442, 573-585) may or may not possess a snout. They may or may not possess confluent gular sutures. When they do, the condition is the same as in other Coleoptera, except that the invaginations are apt to be more extensive. They may or may not possess a labrum. There is no definite character of the head-capsule by which the Rhynchophora as a group can be separated from other Coleoptera. The affinities of this group are not at all clear. The condition of the dorsal surface throughout the groups is most variable, and can be relied upon but little to furnish evidence of the degree of relationship. On the ventral surface the condition is much more stable, and probably much more reliable in indicating affinities. The tentorium is less variable than the dorsal surface, and less stable than the ventral surface. Weighing the evidence presented in this study, two large groups of most of the families can be made. The Lymexyloidea, the Cupesoidea, the Mordelloidea, the Elateroidea, the Dryopoidea, the Dascilloidea, the Byrrhoidea, the Cucujoidea, the Tenebrionoidea, 47] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 47 and the Bostrichoidea should probably be grouped together, while the characteristic families of the Cantharoidea, the Staphylinoidea, and the Silphoidea should perhaps be grouped with the Adephaga and Hydro- philoidea. The Scarabaeoidea may also be included in this latter group. The affinities of the Cerambycoidea and the Rhynchophora are too vague to include either in the two larger groups. 48 ILLINOIS BIOLOGICAL MONOGRAPHS [48 SUMMARY 1. This investigation deals with the homology of all the structures of the head-capsule of one or more representatives of one hundred and five of the one hundred and nine families of Coleoptera listed by Leng in his recent catalogue. One hundred and forty-six genera have been studied and figured, nearly all representing different important subgroups. 2. This serial study has made it possible to identify the same structures in a wide series of forms, and to definitely fix the homology of all the parts of the head-capsule. 3. Hypothetical types have been constructed, based on the structure of the head-capsule of generalized insects and Coleoptera. These show the Coleoptera to have developed in general a consolidation of sclerites and a heavier chitinization of the head wall, a compacting of the head as a whole, and an approximation of the dorsal and ventral movable parts at the cephalic end. 4, The epicranial suture has been identified in all but two of the genera studied. It has proved a great aid in determining the limits of neighboring parts. What may appear to be a distinct epicranial suture may not even be a suture. It is sometimes distinctly invaginated. Its identity can only be definitely fixed by determining the location of the pretentorinae, which are always associated with it. 5. The limits of the vertex are dependent upon the position of the epicranial suture. In the Rhynchophora nearly all of the snout belongs to the vertex. 6. The unmodified occipital suture has been identified only in the Adephaga. The cephalic end on the ventral surface is always represented by part of a curving ridge, which is present in all but a few genera. 7. The supratentorinae have been identified in a few genera, nearly all of which belong to the Staphylinoidea. 8. The pretentorinae are the great landmarks of the head-capsule and have been identified in all but two genera. They are, in the vast majority of genera, located near the cephalic end of the epicranial arms. A definite determination of the pretentorinae cannot always be made with- out an ental examination of the head. 9. The size and form of the front is dependent upon the position of the epicranial arms. In the Cerambycoidea it is large. In many genera, as illustrated by Omophron, Harpalus, and Tachinus, it is partly or wholly invaginated. It may probably be rudimentary or wholly lost in many genera in which the mesal parts of the epicranial arms have disappeared. 49] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 49 10. What has been called the clypeal suture in such genera as Cicindela and Harpalus is not even a suture, but the line of invagination of the front. 11. The clypeus is always divided into the postclypeus and the pre- clypeus. The preclypeus is with one exception always distinctly mem- branous. It may be as large or larger than the labrum. 12. There is a distinct clypealia present in the Coleoptera and in widely separated groups, such as the Adephaga and the Cerambycoidea. 13. The labrum may be indistinctly determined in both Rhynchophora and other Coleoptera. It may also be quite distinct in some Rhyncho- phora where it is considered to be absent. 14. The submentum is always located distinctly cephalad of the oc- cipital foramen, with a chitinized area between it and the foramen. 15. The metatentorinae may be located on the cephalo-lateral border of the occipital foramen, as in generalized insects, or they may be far cephalad of this location. 16. All that region between the occipital foramen and the submentum is a part of the postgenae, produced by the fusion on the meson of the mesal margins of the postgenae. 17. The gular sutures result from the cephalic migration of the meta- tentorinae. 18. The gula is that area included between the gular sutures, and is, therefore, derived from the postgenae. The majority of the Coleoptera possess a gula that extends no more than half the distance between the occipital foramen and the submentum. 19. The tentorium of the Coleoptera is typically quite similar in form and development to that of generalized insects. Frequent modifications are loss of chitinization, loss of corpotentorium and laminatentorium. Occasionally the pretentorium may be rudimentary. The functions of the absent parts are assumed by other parts of the tentorium, or by the pharynx, or the head may be so compact and chitinized that a tentorium is no longer needed. 20. The cephalic migration of the submentum, and the subsequent formation of an indistinguishable area between it and the occipital fora- men is due either to the migration caudad of the occipital foramen or to the cephalic pull on the mouth-parts or to both. The cephalic migration of the metatentoria and, therefore, the metatentorinae, with consequent pro- duction of the gula, is probably due to the cephalic pull on the tentorium to furnish a firmer support for the muscles and tendons of the mouth-parts. 50 ILLINOIS BIOLOGICAL MONOGRAPHS [50 BIBLIOGRAPHY BERLESE, A. 1909. Gli Insetti. 1: 75-114. Milano. Bovine, A., and CHAMPLAIN, A. B. 1920. Larvae of North American beetles of the family Cleridae. Proc. U. S. Nat. Mus., 57:575-649; pl. 42-53. Comstock, J. H. 1893. Evolution and taxonomy. Wilder Quarter Century Book. Pp. 37-113; 3 pls. Comstock, J. H., and Kocw, C. 1902. The skeleton of the head of insects. Amer. Nat., 36:13-45; 29 figs. CRAIGHEAD, F. C. 1920. Biology of some Coleoptera of the families Colydiidae and Bothrideridae. Proc. Ent. Soc. Wash., 22:1-13; 2 pls. Crampton, G. C. 1917. The nature of the veracervix or neck region in insects. Ann. Ent. Soc. Am., 10:187-197. 1920. A comparison of the external anatomy of the lower Lepidoptera and Trichoptera from the standpoint of phylogy. Psyche, 27:23-34; pl. 2-3. 1921. The sclerites of the head, and the mouthparts of certain immature and adult insects. Ann. Ent. Soc. Am., 10:65-103; 86 figs. 1920. La nervation alaire des Coleopteres. Ann. Soc. Ent. Fr., 89:1—50; 30 figs.; 3 pls. GacE, J. Howarp. 1920. The larvae of the Coccinellidae. Ill. Biol. Monographs, 6:49 pp.; 6 pls. GaBAN, C. J. 1911. On some recent attempts to classify the Coleoptera in accordance with their phylogeny. The Entomologist, 45:121-125, 165-169, 214-219, 245-248, 259- 262, 312-314, 348-351, 392-396; 7 figs. GANGLBAUER, L. 1892-1904. Die Kafer von Mitteleuropa. Vol. 1-4, Pt. 1. Wien. HANDLIRSCH, A. 1906-1908. Die Fossilen Insekten und die Phylogenie aS Rezenten Formen. Pp. 1271-80. Leipzig. Hopkins, A. D. 1915. Preliminary lacerations of the superfamily Scolytoidea. Bul. U. S. Bur. Ent., Tech. Ser., No. 17, Pt. 2, pp. 165-237. Hystop, J. A. 1917. The phylogeny of the Elateridae based on larval characters. Ann. Ent. Soc. Amer., 10:233-263; 10 figs. Kose, H. J. 1901. Vergleichend morphologische Untersuchungen an Coleoptera nebst Grundlagen zu einem System und zur Systematik derselben. Beiheft Arch. Naturg., Fest- schrift Edward von Martens, 89-150; 2 pls. 1908. Mein System der Coleopteren Zeitschr. fiir wissenschaftliche Insekten biologie, IV, p. 116-400. 51) THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 51 1911. Die Vergleichende Morphologie und Systematik der Coleopteren. Premier Congres international d’Entomologie, IT:41-68. LAMEERE, A. 1900. Notes pour la classification des Coleopteres. Ann. Soc. Ent. Belg., 44:355-357. 1903. Nouvelles notes pour la classification des Coleopteres. Ann. Soc. Ent. Belg. 47:155-165. Le Conte, J. L., and Horn, G. H. 1883. Classification of the Coleoptera of North America. Smithsonian Mis. Coll., No. 507. Lene, C. W. 1920. Catalogue of the Coleoptera of America, north of Mexico. 470 pp. Mt. Vernon, N. Y. Morr, F. 1918. Notes on the ontogeny and morphology of the male genital tube in Coleoptera. Trans. Ent. Soc. Lond., 1912:223-229; 10 pls. OrcHyMont, A. ’d 1916. Notes pour la classification et la eer des Palpicornia. Ann. Soc. Ent. Fr., 85:91-106; 6 figs. PETERSON, A. 1915. Morphological! studies on the head and mouth-parts of the Thysanoptera. Ann. Ent. Soc. Amer., 8:20-67; 7 pls. 1916. The head-capsule and mouth-parts of Diptera. Ill. Biol. Monographs, 3:1-112; 25 pls. Ritey, W. A. 1904. The embryological development of the skeleton of the head of Blatta. Amer. Nat., 38:777-810; 12 figs. ScutopTE, J. C. 1861-1883. De Metamorphosi Eleutheratorum Observationes: Bidrag til Insekternes Udviklings-historie. 2 vols.; 86 pls. Kjobenhaven. SHARP, D. 1909. Insects. Cambridge Nat. Hist., 6:184-298. SHarp, D., and Murr, F. 1912. The comparative anatomy of the male genital tube in Coleoptera. Trans. Ent. Soc. Lond., 1912:477-639; pl. 42-78. StTRAUSS-DuRCKHEM, H. E. 1828. Considerations generales sur l’anatomie comparee des animaux articules, aux- quelles on a joint l’anatomie descriptive du hanneton vulgaire. Paris. 19+ 434 pp. 10 double plates. LIBRARY DNIVERSITY OF ILLINOIS URBANA hh A, mani Yea ce Rat if » a ¥ Uniwsancteld a0: Sy ae ae OR insane a Kamit pieeshiy oth 6 oan sah seine st bac 't 5) Mee plasenil 4 pote $85 §: Rhy Se eis sada min ead ieconpenete AR COREY sii ; Rana s wepioesnlee 5 re ao aan aN A Pra oat: cry : 4 Eee 4 : Yd ne sete Om i ws ‘ fod Tas sr is od en‘ hi ' 7 Ey Fe | Sa Tamas ig eaeate / 53] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY PEATE. 54 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Vig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. — SOO ONAN PWN Chi — jt Bm W Dd ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE I DORSAL ASPECT OF THE HEAD . Hypothetical type. . Tetracha carolina. . Cicindela formosa. . Calosoma calidum. . Harpalus erraticus. . Amphizoa lecontet. . Omophron americanum. . Peltodytes 12-punctatus. . Cybister fimbriolatus. . Dineutes americanus. Hydraena marginicollis. . Hydroscapha natans. . Hydrous triangularis. . Hydrophilus obtusatus. 15: . Brathimus nitidus. . Leptinus testaceus. . Necrophorus carolinus. . Clambus puberulus. . Connophron fossiger. . Molamba lunata. . Stenus flavicornis. . Harpalus erraticus, cross-section of cephalic end of the dorsal aspect of the head. . Harpalus erraticus, showing invagination of the front. Platypsyllus castoris. antacoila antafossa antacoria cervinotum compound eye clypofrons clypealia epicranial arm exoculata epicranial stem front fos fe l oc ol os pe fronto-clypeal suture frontal ridge labrum occiput oculata occipital suture preclypeus pretentorina postclypeus supratentorina vertex (54 ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII STICKNEY HEAD-CAPSULE OF COLEOPTERA PEATE E 56 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE II DORSAL ASPECT OF THE HEAD . Gastrolobium bicolor. . Creophilus villosus. . Tachinus fimbriatus. . Aleochara lata. . Pilopius lacustris. . Fustiger fuchsi. . Limulodes paradoxus. . Sphaerius politus. . Scaphidium quadriguttatum. . Sphaerites glabratus. . Hister memnonius. . Calopteron terminale. . Photinus pyralis. . Phengodes plumosa. . Chauliognathus pennsylvanicus. . Collops nigriceps. . Trichodes nutalli. . Necrobia rufipes. . Hylecoetus lugubris. . Micromalthus debilis. . Cupes concolor. antacoila f front t antafossa fe frontal ridge antacoria i labrum cervinotum pe preclypeus compound eye pn pretentorina clypealia po postclypeus epicranial arm sn supratentorina epicranial stem v vertex [56 ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII STICKNEY HEAD-CAPSULE OF COLEOPTERA PLATE iT A—STICKNEY a ta + 3 : 58 ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE III DORSAL ASPECT OF THE HEAD Fig. 46. Cephaloon lepiurides. Fig. 47. Nacerda melanura. Vig. 48. Tomoxia bidentata. Fig. 49. Macrosiagon dimidiatum. Fig. 50. Epicauta marginata. Fig. 51. Eurystethus debilis. Fig. 52. Othnius sp. Fig. 53. Pytho planus. Fig. 54. Neopyrochroa flabellata. Fig. 55. Macratria murina. Fig. 56. Notoxus anchora. Fig. 57. Zonantes fasciatus. Fig. 58. Cebrio bicolor. Fig. 59. Euthysanius lautus. Fig. 60. Sandalus niger. Fig. 61. Alaus oculatus. Fig. 62. Isorhipis ruficornis. Fig. 63. Throscus chevrolati. Fig. 64. Chalcophora virginiensis. Fig. 65. Psephenus lecontei. aa antacoila fr frontal ridge af antafossa lL labrum ce compound eye pe preclypeus cl clypealia pn pretentorina ea epicranial arm po postclypeus es epicranial stem v vertex jf front ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII STICKNEY HEAD-CAPSULE OF COLEOPTERA BA Ey eat ¥, a < aw -e 4 of By re ate w a) sented — 59] . THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY PLATE. TV 60 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE IV 66. Helichus striatus. 67. Stenelmis sinuata. 68. Heterocerus undatus. 69. Georyssus californicus. 70. Eurypogon niger. 71. Eucinetus morio. 72. Cyphon ruficollis. 73. Chelonarium errans. 74. Dermestes lardarius. 75. Byrrhus americanus. 76. Nosodendron unicolor. 77. Rhysodes americanus. 78. Tenebroides sinuatus. 79. Phenolia grossa. DORSAL ASPECT OF THE HEAD 80. Glischrochilus fasciatus. 81. Rhizophagus bipunctatus. 82. Phyconomus marinus. 83. Cucujus clavipes. 84. Hemipeplus marginipennis. 85. Languria mozardi. 86. Megalodacne fasciata. 87. Derodontus asculatus. aa antacoila af antafossa ce compound eye cl clypealia ea epicranial arm es epicranial stem f front fe frontal ridge 1 labrum ~p preclypeus pn pretentorina po postclypeus pr precoila v vertex [60 ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII STICKNEY HEAD-CAPSULE OF COLEOPTERA PLATE IV 61] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY PLATE V 61 62 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. 88. 89. 90. 91. 92. 93. 94. 95. 96. 97. 98. 99. 100. 101. 102. 103. 104. 105. ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE V DORSAL ASPECT OF THE HEAD Anckhicera ephippiata. Byturus unicolor. Mycetophagus punctatus. Bothrideres geminatus. Philothermus glabriculus. Melanophthalma cavicollis. Phymaphora pulchelia. Endomychus biguitatus. Phalacrus politus. Hippodamia convergens. Adalia bipunctata. Pseudocistela brevis. Alobates pennsylvanica. Tenebrio molitor. Boros unicolor. Arthromacra aenea. Hyporphagus sp. Penthe obliquata. 106. Ptinus brunneus. 107. Sitodrepa panicea. aa antacoila fe frontal ridge a antafossa lL labrum é compound eye pe preclypeus l clypealia pn pretentorina @ epicranial arm po postclypeus § epicranial stem sn supratentorina f front v vertex [62 ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII STICKNEY HEAD-CAPSULE OF COLEOPTERA PLATE V 63] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY PLATE Vi 63 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE VI DORSAL ASPECT OF THE HEAD 108. Bostrichus bicornis. 109. Lyctus planicollis. 110. Sphindus americanus. 111. Plesiocis cribrum. 112. Aphodius fimetarius. 113. Dichelonyx elongata. 114. Pelidnota punctata. 115. Strategus julianus. 116. Osmoderma eremicola. 117. Trox suberosus. 118. Pseudolucanus capreolus. 119. Passalus cornutus. 120. Parandra brunnea. 121. Derobrachus brunneus. 122. Spondylis buprestoides. 123. Glycobius speciosus. 124. Tetraopes tetraophthalmus. 125. Donacia piscatrix. 126. Syneta ferruginea. 127. Criocerus asparagi. aa antacoila f front af antafossa fe frontal ridge ce ch ol ea €0 es compound eye lL labrum chitinized area pe preclypeus clypealia pn pretentorina epicranial arm po postclypeus exoculata v vertex epicranial stem [64 ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII STICKNEY HEAD-CAPSULE OF COLEOPTERA PLATE VI nage _ i ht ee ken } Dien dente eet eA =~ ter eathn jane ‘ey 5 . ae , c be : ee aT a : - oo : ro mo & ) a +f i‘ Wr ee Fare tte rare joo : rh 66 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. 128. 129. 130. i3f. 132. 133. 134. 135, 136. 137. 138. 155. 140. 141. 142. 143. 144. 145. 146. 147 148 ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE VII DORSAL ASPECT OF THE HEAD Cryptocephalus quadruplex. Chrysochus auratus. Leptinotarsa decemlineata. Diabrotica 12-punctata. Blepharida rhois. Anoplitis gracilis. Chelymorpha argus. Pachymerus gleditsiae. Eupsalis minuta. Ithycerus noveboracensis. Eurymycter fasciatus. Rhinomacer pilosus. Rhynchites bicolor. Attelabus analis. Epicaerus imbricatus. Lixus fimbriolatus. Thecesternus humeralis. Sphenophorus aequalis. Platypus flavicornis. . Scolytus quadrispinosus. . Dendroctonus valens. aa antacoila lL labrum af antafossa pe preclypeus an antacoria pn pretentorina ce compound eye po postclypeus cl clypealia pr precoila €a epicranial arm pi pretentorium es epicranial stem v vertex f front VOLUME VIII ILLINOIS BIOLOGICAL MONOGRAPHS PLATE Vil ERA HEAD-CAPSULE OF COLEOPT STICKNEY 67| THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY PLATE VIII 67 68 ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE VIII VENTRAL ASPECT OF THE HEAD Fig. 149. Hypothetical type. Fig. 150. Tetracha carolina. Fig. 151. Cicindela formosa. Fig. 152. Calosoma calidum. Fig. 153. Harpalus erraticus. Fig. 154. Amphizoa lecontei. Fig. 155. Omophron americanum. Fig. 156. Peltodytes 12-punctatus. Fig. 157. Cybister fimbriolatus. Fig. 158. Dineutes americanus. Fig. 159. Hydraena marginicollis. Fig. 160. Hydroscapha natans. Fig. 161. Hydrous triangularis. Fig. 162. Hydrophilus obtusatus. Fig. 163. Platypsyllus castoris. Fig. 164. Brathinus nitidis. Fig. 165. Leptinus testaceus. Fig. 166. Necrophorus carolinus. Fig. 167. Clambus puberulus. Fig. 168. Connophron fossiger. Fig. 169. Molamba lunata. Fig. 170. Stenus flavicornis. aa = antacoila mt metatentorium af antafossa oc — occiput an antacoria os occipital suture ccp cervepimeron pa _postgena ccs cervepisternum pe _preclypeus cct cervisternum pl __paracoila ce compound eye pn _ pretentorina gu guia pr precoila gub gula bar pt pretentorium in invagination pil postcoila inl line of invagination sm submentum l labrum v vertex mn metatentorina ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII STICKNEY HEAD-CAPSULE OF COLEOPTERA PLATE VITI ‘ POTN ke Bs h * , ’ * s hein i } v ie \ ri com i — | . PLATE IX 70 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. gud 1m inl ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE IX VENTRAL ASPECT OF THE HEAD . Gasirolobium bicolor. . Creophilus villosus. . Tachinus fimbriatus. . Aleochara lata. . Pilopius lacustris. . Fustiger fuchsi. . Limulodes paradoxus. . Sphaerius politus. . Scaphidium quadriguitaium. . Sphaerites glabratus. . Hister memnonius. . Calopteron terminale. . Photinus pyralis. . Phengodes plumosa. . Chauliognathus pennsylvanicus. . Chauliognathus pennsylvanicus, cross-section, showing invagination of gula. . Cantharis bilineatus. . Collops nigriceps. . Trichodes nutalli. . Necrobia rufipes. . Hylecoetus lugubris. . Micromalthus debilis. antacoila l labrum antafossa mn metatentorina antacoria mt metatentorium cervepimeron os occipital suture cervepisternum pa postgena ~ cervisternum pe preclypeus compound eye pl _ paracoila chitinized area pn pretentorina epicranial arm pr precoila gula pt pretentorium gula bar pil postcoila invagination sm submentum line of invagination v vertex 1) ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII STICKNEY HEAD-CAPSULE OF COLEOPTERA PLATE, LX 72 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE X VENTRAL ASPECT OF THE HEAD . Cupes concolor. . Cephaloon lepturides. . Nacerda melanura. . Tomoxia bidentata. . Macrosiagon dimidiatum. . Epicauta marginata. . Eurystethus debilis. . Otknius sp. . Pytho planus. . Neopyrochroa flabellata. . Macratria murina. . Notoxus anchora. . Zonantes fasciatus. . Cebrio bicolor. . Euthysanius lautus. . Sandalus niger. . Alaus oculatus. . Isorhipis ruficornis. . Throscus chevrolati. . Chalcophora virginiensis. . Psephenus lecontez. antacoila mn metatentorina antafossa os occipital suture cervepimeron pa postgena cervepisternum pe — preclypeus cervisternum pl paracoila compound eye pn pretentorina epicranial arm pr precoila gula pil postcoila invagination sm submentum line of invagination v vertex labrum [72 ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII STICKNEY HEAD-CAPSULE OF COLEOPTERA PLATE X 73] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY PLATE XI 73 74 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE XI VENTRAL ASPECT OF THE HEAD . Helichus striatus. . Stenelmis sinuata. . Heterocerus undatus. . Georyssus californicus. . Eurypogon niger. . Eucinetus morio. . Cyphon ruficollis. . Chelonarium errans. . Dermestes lardarius. . Byrrhus americanus. . Nosodendron unicolor. . Rhysodes americanus. . Tenebroides sinuatus. . Phenolia grossa. . Glischrochilus fasciatus. . Rhizophagus bipunctatus. . Phyconomus marinus. . Cucujus clavipes. . Hemipeplus marginipennis. . Languria mozardi. . Megalodacne fasciata. . Derodontus maculatus. antacoila od odontoidea antafossa os occipital suture cervepimeron pa postgena cervepisternum pe _ preclypeus cervisternum pl __paracoila compound eye pn pretentorina epicranial arm pr precoila gula pil postcoila line of invagination sm submentum labrum v vertex metatentorina [74 ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII \ BY = y \ v 7 / / SrICKNEY HEAD-CAPSULE OF COLEOPTERA PLATE Xl 75] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY PLATE Xi 76 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE XII VENTRAL ASPECT OF THE HEAD . Anchicera ephippiata. . Byturus unicolor. . Mycetophagus punctatus. . Bothrideres geminatus. . Philothermus glabriculus. . Melanopthalma cavicollis. . Phymaphora pulchelia. . Endomychus biguttatus. . Phalacrus politus. . Hippodamia convergens. . Adalia bipunctata. . Pseudocistela brevis. . Alobates pennsylvanica. . Tenebrio molitor. . Boros unicolor. . Arthromacra aenea. . Hyporphagus sp. . Penthe obliquata. . Ptinus brunneus. . Sitodrepa panicea. . Bostrichus bicornis. . Lyctus planicollis. antacoila mn metatentorina antafossa os occipital suture antacoria pa postgena cervepimeron pe preclypeus cervepisternum pl paracoila compound eye pn pretentorina epicranial arm pr _ precoila gula pt pretentorium invagination pil postcoila line of invagination sm submentum labrum v vertex 176 ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII STICKNEY HEAD-CAPSULE OF COLEOPTERA PLATE XII 77) THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY PLATE XIII 78 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE XIII VENTRAL ASPECT OF THE HEAD . Sphindus americanus. . Plesiocis cribrum. . Aphodius fimetarius. . Dichelonyx elongata. . Pelidnota punctata. . Strategus julianus. . Osmoderma eremicola. . Trox suberosus. . Pseudolucanus capreolus. . Passalus cornutus. . Parandra brunnea. . Derobrachus brunneus. . Spondylis buprestoides. . Glycobius speciosus. . Tetraopes tetrophthalmus. . Donacia piscatrix. . Syneta ferruginea. . Criocerus asparagi. . Cryptocephalus quadruplex. . Chrysochus auratus. . Leptinotarsa decemlineata. . Diabrotica 12-punctata. antacoila of occipital foramen antafossa pa postgena antacoria pe preclypeus cervepimeron pl =paracoila cervepisternum pn pretentorina compound eye pr precoila epicranial arm pi pretentorium gula pil postcoila ~ labrum sm submentum metatentorina v vertex [78 ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII STICKNEY HEAD-CAPSULE OF COLEOPTERA PLATE XIII 79] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY PLATE XIV 80 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE XIV VENTRAL ASPECT OF THE HEAD . Blepharida rhois. . Anoplitis gracilis. . Chelymorpha argus. . Pachymerus gleditsiae. . Eupsalis minuta. . Ithycerus noveboracensis. . Eurymycter fasciatus. . Rhinomacer pilosus. . Rhynchites bicolor. . Aitelabus analis. . Epicaerus imbricatus. . Lixus fimbriolatus. . Thecesternus humeralis. . Sphenophorus aequalis. . Platypus flavicornis. . Scolytus quadrispinosus. . Dendroctonus valens. LATERAL ASPECT OF THE HEAD . Tetracha carolina. . Cicindela formosa. . Calosoma calidum. . Harpalus erraticus. . Amphizoa lecontet. | . Omophron americanum. . Peltodytes 12-punctatus. . Cybister fimbriolatus. . Dineutes americanus. antacoila mé metatentorium antafossa oc occiput antacoria ol _ oculata cervepimeron os occipital suture cervepisternum pa postgena compound eye pe preclypeus clypealia pl _paracoila corpotentorium pn pretentorina epicranial arm po postclypeus exoculata pr precoila front pi pretentorium frontal ridge pil postcoila gula sm submentum gula bar sn supratentorina labrum st supratentorium laminatentorium v vertex metatentorina ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII SLICKNEY HEAD-CAPSULE OF COLEOPTERA PLA LE, XLV 81] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY PLATE XV 82 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. 306. 307. 308. 309. 310. 311. 52. 313. 314. 315. 316. 317. 318. 319. 320. 321. a2, 323. 324. ccp ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE XV LATERAL ASPECT OF THE HEAD Hydraena marginicollis. Hydroscapha natans. Hydrous triangularis. Hydrophilus abtusatus. Platypsyllus castoris. Brathinus nitidus. Leptinus testaceus. Necrophorus carolinus. Clambus puberulus. Connophron fossiger. Molamba lunatic. Sienus flavicornis. Gastrolobium bicolor. Creophilus villosus. Tachinus fimbriatus. Aleochara lata. Pilopius lacustris. Fustiger fuchsi. Limulodes paradoxus. antacoila Ut laminatentorium antafossa mn metatentorina cervepimeron mt metatentorium cervepisternum ol oculata compound eye pa postgena chitinized area pe preclypeus clypealia pl _ paracoila corpotentorium pn pretentorina epicranial arm po postclypeus front pr __ precoila frontal ridge pi pretentorium gula sm submentum gula bar st | supratentorium labrum v vertex {82 ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII STICKNEY HEAD-CAPSULE OF COLEOPTERA PLATE XV + . 7 | | hi oe : a 83] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY PLATE XVI 83 84 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE XVI LATERAL ASPECT OF THE HEAD . Sphaerius politus. . Scaphidium quadriguttatum. . Sphaerites glabratus. . Hister memnonius. . Calopteron ierminale. . Photinus pyralis. . Phengodes plumosa. . Chauliognathus pennsylvanicus. . Collops nigriceps. . Trichodes nutalli. . Necrobia rufipes. . Hylecoetus lugubris. . Micromalthus debilis. . Cupes concolor. . Cephaloon lepturides. . Nacerda melanura. . Tomoxia bidentata. . Macrosiagon dimidiatum. . Epicauta marginata. . Eurystethus debilis. . Othinus sp. antacoila gub gula bar antafossa l labrum antacoria Ut laminatentorium cervepimeron mn metatentorina cervepisternum. mé metatentorium cervesternum. pe preclypeus compound eye pl _ paracoila chitinized area pn pretentorina clypealia po _postclypeus corpotentorium pt pretentorium epicranial arm pil postcoila front sm submentum frontal ridge st supratentorium gula v vertex (84 ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII STICKNEY HEAD-CAPSULE OF COLEOPTERA PLATE XVI 85] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY PLATE XVII 86 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. 346. 347. 348. 349. 350. Sok: 352. 353. 354. 355. 356. Eye 358. 359. 360. 361. 362. 363. 364. 365. 366. 367. aa af an ccp ces ce ch cl ct ea fe gu m ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE XVII LATERAL ASPECT OF THE HEAD Pytho planus. Neopyrochroa flabellata. Macratria murina. Notoxus anchora. Zonantes fasciatus. Cebrio bicolor. Euthysanius lautus. Sandalus niger. Alaus oculatus. Tsorhipis ruficornis. Throscus chevrolatt. Chalcophora virginiensis. Psephenus lecontet. Helichus striatus. Stenelmis sinuata. Heterocerus undatus. Georyssus californicus. Eurypogon niger. Eucinetus morio. Cyphon ruficollis. Chelonarium errans. Dermestes lardarius. antacoila l labrum antafossa it laminatentorium antacoria mn metatentorina cervepimeron mé metatentorium cervepisternum pe preclypeus compound eye pl __ paracoila chitinized area pn pretentorina clypealia po postclypeus corpotentorium pt pretentorium. epicranial arm pu postcoila frontal ridge sm submentum gula st supratentorium invagination v vertex (86 ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII SLICKNEY HEAD-CAPSULE OF COLEOPTERA PLATE XVII 87] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY PLATE XVIII 88 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE XVIII LATERAL ASPECT OF THE HEAD . Byrrhus americanus. . Nosodendron unicolor. . Rhysodes americanus. . Tenebroides sinuatus. . Phenolia grossa. . Glischrochilus fasciatus. . Rhizophagus bipunctatus. . Phyconomus marinus. . Cucujus clavipes. . Hemipeplus marginipennis. . Languria mozardi. . Megalodacne fasciata. . Derodontus maculatus. . Anchicera ephippiata. . Byturus unicolor. . Mycetophagus punctatus. . Bothrideres geminatus. . Philothermus glabriculus. . Melanophthalma cavicollis. . Phymaphora pulchella. . Endomychus biguttatus. . Phalacrus politus. antacoila l¢ laminatentorium antafossa mn metatentorina antacoria mt metatentorium antacava od odontoidea cervepimeron pe preclypeus cervepisternum pl _ paracoila compound eye pn pretentorina chitinized area po postclypeus clypealia pt pretentorium corpotentorium pil postcoila epicranial arm sm submentum frontal ridge st supratentorium gula v vertex labrum [88 ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII 1 i , 1 ' 1 1 ! ! Hey By nit ats! STICKNEY HEAD-CAPSULE OF COLEOPTERA PLATE XVIII 89] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY PLATE XIX 89 90 gu ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE XIX LATERAL ASPECT OF THE HEAD . Hippodamia convergens. . Adalia bipunctatus. . Pseudocistela brevis. . Alobates pennsylvanica. . Tenebrio molitor. . Boros unicolor. . Arthromacra aened. . Hyporphagus sp. . Penthe obliquata. . Ptinus brunneus. . Sttodrepa panicea. . Bostrichus bicornis. . Lyctus planicollis. . Sphindus americanus. . Plesiocis cribrum. . Aphodius fimetarius. . Dichelonyx elongata. . Pelidnota punctata. . Strategus julianus. . Osmoderma eremicolla. . Trox suberosus. . Pseudolucanus capreolus. . Passalus cornutus. antacoila l labrum antafossa mn metatentorina antacoria mt metatentorium cervepimeron ol _—oculata cervepisternum pe preclypeus - compound eye pl _ paracoila chitinized area pn pretentorina clypealia po _postclypeus corpotentorium pt pretentorium epicranial arm sm submentum frontal ridge st supratentorium gula v vertex [90 ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII STICKNEY HEAD-CAPSULE OF COLEOPTERA PLATE XIX - a ’ ¢ = a | o ‘ * i \ s4s , p ‘ 2 ‘ SS ‘ e 2 A. ’ = ' ‘ { j “ = \ e 4, * = 4 a e tig 2 ob ee . ‘ Pi fe ‘ ) - ! : ; ; i f f r J 7 rs \ = ; 2 91] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY PLATE XX 91 92 - 413. . 414, . 415. . 416. . 417. . 418. . 419. - 420. - 421. . 422. - 423, . 424. - 425. . 426. . 427. . 428. . 429. . 430. . 431. - 432. - 433. . 434, . 435. ccp ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE XX LATERAL ASPECT OF THE HEAD Passalus cornutus. Parandra brunnea. Derobrachus brunneus. Spondylis buprestoides. Glycobius speciosus. Teiraopes tetraophthalmus. Donacia piscatrix. Syneia ferruginea. Criocerus asparagi. Cryptocephalus quadruplex. Chrysochus auratus. Leptinotarsa decemlineata Diabrotica 12-punctata. Blepharida rhois. Anoplitis gracilis. Chelymor pha argus. Pachymerus gleditsiae. Eupsalis minuta. Ithycerus noveboracensis. Eurymycter fasciatus. Rhinomacer pilosus. Rhynchites bicolor. Aittelabus analis. antacoila lt laminatentorium antafossa mn metatentorina antacoria mt metatentorium antacava ol _oculata cervepimeron pa postgena cervepisternum pe _ preclypeus. compound eye pl _ paracoila chitinized area pn pretentorina clypealia po _ postclypeus corpotentorium pr precoila epicranial arm pt pretentorium frontal ridge sm submentum gula st supratentorium labrum v vertex [92 ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII v Kathy V# Hr @r-- Hv ff x a L V& A STICKNEY HEAD-CAPSULE OF COLEOPTERA PLATE XX eG. Gee hatte A at ee ‘ 4 ; lJ + F “ Lt dve ’ ~ if oT] 5 rte : 3% , a0 ‘ 7 aw, eet. 93] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY PLATE XXI 93 94 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. 436. 437. 438. 439, . Platypus flavicornis. . Scolytus quadrispinosus. . Dendrocionus valens. ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE XXI LATERAL ASPECT OF THE HEAD Epicaerus imbricatus. Lixus fimbriolatus. Thecesternus humeralis. Sphenophorus aequalis. ENDOSKELETON OF THE HEAD . Hypothetical type. . Tetracha carolina. . Cicindela formosa. . Calosoma calidum. . Harpalus erraticus. . Amphizoa lecontei. . Omophron americanum. . Peltodytes 12-punctata. . Cybister fimbriolatus. . Dineutes americanus. . Hydraena marginicollis. . Hydroscapha natans. . Hydrous triangularis. . Hydrophilus obtusatus. . Platypsyllus castoris. antafossa mn wmetatentorina antacava mt metatentorium cervepimeron od odontoidea cervepisternum pl paracoila — compound eye pn _ pretentorina clypealia pr precoila corpotentorium pt pretentorium epicranial arm pil postcoila invagination sm submentum labrum sn supratentorina laminatentorium st supratentorium [94 ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII SrICKNEY HEAD-CAPSULE OF COLEOPTERA PLATE XXI % 95] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY PLATE XXII 95 96 ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE XXII ENDOSKELETON OF THE HEAD Fig. 458. Brathinus nitidus. Fig. 459. Leptinus testaceus. Fig. 460. Necrophorus carolinus. Fig. 461. Clambus puberulus. Fig. 462. Connophron fossiger. Fig. 463. Stenus flavicornis. Fig. 464. Gastrolobium bicolor. Fig. 465. Creophilus villosus. Fig. 466. Tachinus fimbriatus. Fig. 467. Aleochara lata. Fig. 468. Pilopius lacustris. Fig. 469. Limulodes paradoxus. Fig. 470. Sphaerius politus. Fig. 471. Scaphidium quadriguttatum. Fig. 472. Sphaerites glabratus. Fig. 473. Hister memnonius. Fig. 474. Calopieron terminale. Fig. 475. Photinus pyralis. Fig. 476. Phengodes plumosa. Fig. 477. Chauliognathus pennsylvanicus. Fig. 478. Collops nigriceps. Fig. 479. Trichodes nutalli. Fig. 480. Necrobia rufipes. Fig. 481. Hylecoetus lugubris. af antafossa mn metatentorina an antacoria mt metatentorium av antacava od odontoidea ccp cervepimeron pl paracoila — ccs cervepisternum pn pretentorina ce compound eye pr precoila ct —_ corpotentorium pt pretentorium gub gular bar pil postcoila l labrum sn supratentorina im invagination st supratentorium lt laminatentorium ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII NY) \ ait ave Wii) (Ny hy STICKNEY HEAD-CAPSULE OF COLEOPTERA PLATE XXII 97) THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY PLATE XXIII 98 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE XXIII ENDOSKELETON OF THE HEAD . Cupes concolor. Cephaloon lepturides. . Nacerda melanura. Tomoxia bidentata. Macrosiagon dimidiatum. Epicauta marginata. Eurystethus debilis. . Othnius sp. . Pytho planus. Neopyrochroa flabellata. . Macratria murina. . Notoxus anchora. . Zonantes fasciatus. Cebrio bicolor. . Euthysanius lautus. . Sandalus niger. . Alaus oculatus. . Isorhipis ruficornis. . Throscus chevrolati. . Chalcophora virginiensis. . Psephenus lecontet. . Helichus striatus. 3 . Stenelmis sinuata. . Heterocerus undatus. antafossa lt laminatentorium cervepimeron mn metatentorina cervepisternum mt metatentorium cervesternum od _odontoidea compound eye pl paracoila chitinized area pr precoila corpotentorium pt pretentorium epicranial arm pil postcoila invagination st supratentorium labrum [98 ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII SIlUICKNE Y HEAD-CAPSULE OF COLEOPTERA PLATE XXIII 99] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY PLATE XXIV 100 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE XXIV ENDOSKELETON OF THE HEAD . Georyssus californicus. . Eurypogon niger. . Eucinetus morio. . Cyphon ruficollis. . Chelonarium errans. . Dermestes lardarius. . Byrrhus americanus. . Nosodendron unicolor. . Rhysodes americanus. . Tenebroides sinuatus. . Phenolia grossa. . Glischrochilus fasciatus. . Rhizophagus bipunctatus. - Phyconomus marinus. . Cucujus clavipes. . Hemipeplus marginipennis. . Languria mozardi. . Megalodacne fasciata. . Derodontus maculatus. . Anchicera ephippiata. . Byturus unicolor. . Mycetophagus punctatus. . Bothrideres geminatus. . Philothermus glabriculus. . Melanophthalma cavicollis. - Phymaphora pulchella. . Endomychus biguttatus. antafossa mn metatentorina cervepimeron mé metatentorium cervepisternum od _odontoidea cervisternum pl paracoila compound eye fr precoila corpotentorium pi pretentorium invagination pil postcoila labrum st supratentorium laminatentorium [100 VOLUME VIII ILLINOIS BIOLOGICAL MONOGRAPHS PLATE XXIV CAPSULE OF COLEOPTERA HEAD- SLICKNEY 101] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 101 PLATE XXV 102 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Vig. Fig. Fig. Fig. 533. 534. 535, 536. 537. 538. 539. 540. 541. 542. 543. 544, 545. 546. 547. 548. 549. 550. 551. 552. 553. . Trox suberosus. . Pseudolucanus capreolus. 556. 557. 558. ccp ccs ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE XXV ENDOSKELETON OF THE HEAD Phalacrus politus. Hippodamia convergens. Adalia bipunctata. Pseudocistela brevis. Alobates pennsylvanica. Tenebrio molitor. Boros unicolor. Arthromacra aenea. Hyporphagus sp. Penthe obliquata. Ptinus brunneus. Sitodrepa panicea. Bostrichus bicornis. Lyctus planicollis. Sphindus americanus. Plesiocis cribrum. Aphodius fimetarius. Dichelonyx elongata. Pelidnota punctata. Strategus julianus. Osmoderma eremicola. Passalus cornutus. Parandra brunnea. Derobrachus brunneus. antafossa mn metatentorina cervepimeron mé metatentorium cervepisternum od odontoidea cervisternum pl paracoila compound eye po postclypeus corpotentorium pr precoila epicranial arm pt pretentorium invagination pil postcoila labrum sm submentum laminatentorium st supratentorium [102 ILLINOIS BIOLOGICAL MONOGRAPHS VOLUME VIII Ay STICKNEY HEAD-CAPSULE OF COLEOPTERA PLATE XXV 103] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 103 PLATE XXVI 104 Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. ILLINOIS BIOLOGICAL MONOGRAPHS EXPLANATION OF PLATE XXVI ENDOSKELETON OF THE HEAD . Spondylis buprestoides. . Glycobius speciosus. . Tetraopes tetraophthalmus. . Donacia piscatrix. . Syneta ferruginea. . Criocerus asparagi. . Cryptocephalus quadruplex. . Chrysochus auratus. . Leptinotarsa decemlineata. . Diabrotica 12-punctata. . Blepharida rhois. . Anoplitis gracilis. . Chelymor pha argus. . Pachymerus gleditsiae. . Eupsalis minuta, . Ithycerus noveboracensis. . Eurymycter fasciatus. . Rhinomacer pilosus. . Rhynchites bicolor. . Attelabus analis. . Epicaerus imbricatus. . Lixus fimbriolatus. . Thecesternus humeralis. . Sphenophorus aequalis. . Platypus flavicornis. . Scolytus quadrispinosus. . Dendroctonus valens. antafossa mt metatentorium cervepisternum od odontoidea compound eye pl paracoila corpotentorium pr precoila epicranial arm pi pretentorium invagination pill postcoila laminatentorium st supratentorium metatentorina [104 VOLUME VIII OIS BIOLOGICAL MONOGRAPHS = / WELT N PLATE XXVI HEAD-CAPSULE OF COLEOPTERA SLICKNEY ch ee oc Dey te “Ud wae ANY Wnt val AMEN Wy LRT i My} Wins MER FC ty NT ta if Ney Se he Ny fe ees aA A ati VERSITY OF ILLINOIS-URBANA WN 3 0112 065097260