ANTENNA OF LEriDOPTKRA. 27 



markedly in the degree of specialization both sexes have been studied, 

 but in the tables and descriptions which follow reference is always 

 made to the conditions found in the males, unless special mention is 

 made that the case is otherwise. 



JUGAT^E. 



The suborder Jugataj was established by Professor Comstock, and 

 was based principally upon important characters in some of the wing 

 structures which represent specializations differing in kind from those 

 of analogous structures in insects of the other suborder.* This 

 division of the order into the Jugatse and Frenatre represents the 

 earliest dichotomous division of the stem form of the Lepidoptera, 

 The antennal character which distinguishes between the two lines 

 of descent is the presence in the first of fixed-hairs upon the surface 

 of the clavola ; and in the second, of plates or their modifications. 

 Professor Kellogg has already pointed out that the Jugatie possess 

 fixed hairs upon the wing-membranes ; and he regards them as an 

 example of a " persistence of a primitive wing-covering, probably 

 represented in the wing-covering of the living Trichoptera." It may 

 be added that he believes their absence among the Frenatie is due 

 to a disai)pearance. I believe that the system of fixed hairs is a 

 distinct kind of specialization, closely resembling that found in the 

 Trichoptera and also in the Diptcra and Hymenoptera ; while the 

 system of plates with its later developments is just as distinct and 

 differs from the first. If this is so, it indicates that the Jugatse are 

 more closely related to the Trichoptera than to the Frenatse ; that 

 the stem form passed down in two lines of descent, and that the 

 Frenataj represent one, while the Jugatse and the Trichoptera rep- 

 resent subsequent divisions of the other. This conclusion would 

 really mean that the Jugatte are Trichoptera rather than Lepidop- 

 tera. It may at first sight seem that the character of the surface 

 coverhig is a trivial one and not worthy of so much attention. Dar- 

 win, however, laid it down as a geneaal rule that " the le»s any part 

 of an organization is concerned with special hal)its, the more impor- 

 tant it becomes for classification." We may recall in this connec- 

 tion that certain features apparently of little physiological import- 

 ance often afford the most reliable characters. This is especially 

 true of surface covering, e. g. hair of Mammals, feathers of Birds, 

 scales of Reptiles, etc. 



* The Descent of the Lepidopteiii. J. H. Comstock, Proc. Am. Ass. Adv. So. 

 vol. xli, 1892, pp. 199-200. 



TRANS. AM. KNT. SOC. XXIII. FKBRUARY, 1896. 



