.54 Bulletin 64. 



each sex taken determined. In the determination of species I 

 found the male genital organs to be of great value. Many indi- 

 viduals after being in the trap-lantern could not be recognized by 

 the markings. After a little experience it was only a few minutes' 

 work to expose the genitalia of a softened individual. These 

 organs, after the insect is softened, can be pushed into sight with 

 a point of a pin and a glance is usually enough to determine the 

 species. 



Venation of the Wings. — The figures illustrating the vena- 

 tion of the wings are made from camera lucida drawings of 

 bleached specimens. Great care was taken to represent accur- 

 ately the outlines of the wings and the courses of the veins, but 

 it was impracticable to use the same scale of enlargement for all ; 

 this has been done, however, on Plates XIII and XIV. 



The nomenclature of wing veins adopted is that of Redten- 

 bacher as modified by Professor Comstock in his essay on Evolu- 

 tion and Taxonomy. It seems unnecessary to describe the 

 specific characteristics of the venation as these are shown in the 

 plates better than I can describe them. Within the genus there 

 are some specializations worthy of note. In the fore wing, vein 

 III is five-branched except in C. viinimelhis, where it is but two- 

 branched ; vein VII is apparently four-branched in all the species 

 except C. minimeUus, where vein V^ has coalesced with vein V3. 

 In the hind wing the frenulum is a single stout spine in the male, 

 while in the female it consists of two distinct spines except in C. 

 caliginosellus and C. hulstellus, where it is divided at the tip only. 

 The base of vein III is more or less rudimentary and a stump of 

 vein V,,^., persists in some cases. Vein VII is apparently four- 

 branched except in C. minimellua, where it is but three-branched. 



Structure of the External Reproductive Organs. — As 

 no one writer, to my knowlege, has used a complete set of com- 

 prehensive terms for these important organs, it will be necessary 

 to define the nomenclature used. In the male there are two pairs 

 of lateral clasping organs, termed collectively, the clasps (PL V, 

 Fig. I, V and li). In this genus the outer pair appear to 

 be more or less protective in function and are termed valves (PI. 

 V, Fig. I, z'). The inner pair are more or less chitinous 

 and function as grappling hooks, the harpes. (PI. V, Fig. i, /^.) 

 Between the clasps is a more or less chitinous organ, the intromit- 



