ILLIXOIS 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-sLx 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 

 head 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 number of 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 .\DEPH.\G.\ 

 Caraboide.4. 

 1. Cicindelidae. 



Megacephalini.— Tetracha Carolina (Figs. 2, 150, 297, 444). 

 Cicindehni.— Cicindela formosa (Figs. 3, 151, 298, 445). 



