150 CASEY 



The series of puncttilata and imiricata before me are com- 

 posed of twelve and nineteen specimens respectively, that of 

 angustula consisting of seven specimens, rendering the differ- 

 ences alluded to above patent at a glance ; the types of densa 

 and frontalis are still unique. In his original description of 

 Ccelotaxis (Trans. Am. Ent. Soc, V, 1876, p. 200), Dr. Horn 

 makes no mention of its most conspicuous distinguishing char- 

 acter, which is the minute and subobsolete scutellum, and, in 

 the accompanying table, interposes Cceliis between Ccelotaxis 

 and Eusattus. It is true that the very great obliquity of trun- 

 cature of the basal anterior tarsal joint, which varies but little 

 throughout the genus, gives rise to the appearance of a short 

 spur-like process homologous with the long process of Ccehis, 

 but this is simply a variation of the structure of this joint char- 

 acterizing Coniontis^ due to the more developed burrowing 

 habits of Ccelotaxis^ as shown by the fimbriate margins of the 

 body in the latter genus. At the same time, the long spur of 

 Cceliis is merely a still further development of this character, 

 surviving in more or less developed form from the common arche- 

 types of the subfamily Coniontinae, wholly lost in Eusattus 

 and allies and most developed in the burrowing types, such as 

 Ccelus. It simply proves that Coelus and Coniontis are descended 

 from the same ancestors, the remoteness of which can only be 

 conceived on considering the very radical antennal differences, 

 which must have taken untold ages to develop, and of which no 

 trace of any surviving intermediate form has yet come to light. 



Tribe Ccelini. 



In proposing a separate tribe based upon virtually a single 

 structural character, such as obtains in the case of Ctrlus with 

 one or two allied genera, much should depend upon the nature 

 of this differential feature, its degree of development and its 

 constancy or consistency. The antennae throughout the series 

 of genera discussed hitherto in this paper, constituting the Con- 

 iontini, are greatly developed, long and generally slender, while 

 in Ccelus and allies these organs assume a totally different 

 form, being very small, thicker and more compact. If there 

 were any intermediate living forms, and I cannot regard the 



