THE HEAD-CAPSVLE OF COLEOPTERA— STICK SEY 



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 genital 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), Boving 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, 



