Evohdion and Taxonorny 105 



Fig. 6). In the hind wings veins IX and XI are well pre- 

 served and the distal part of vein VIII is represented by a 

 slight thickening of the membrane. The second branch of 

 media in both wings nearly retains its primitive position ; in 

 fact it can not be said that a tendency to migrate in either di- 

 rection has been established, although the base of media is 

 lost. In the fore wings the third branch of media, and in the 

 hind wings both the first and third branches of this vein, have 

 become consolidated in each case with the adjacent vein to 

 a remarkable extent. Here is a high degree of specialization 

 in one direction correlated with a comparatively generalized 

 condition of certain other characters. Although subcosta 

 and radius of the hind wings are closely parallel, they are 

 distinct. The clothing of the wings is extremely general- 

 ized, consisting chiefly of narrow scales, with a single notch 

 at the extremity, and scattered irregularly over the surface 

 of the wing. The larvae resemble those of some of the 

 Notodontidae. Family Dioptid.^. 



FF. The Geometro-Bombycids and the Geometrids. — Under 

 this head I group three families that have been quite widely 

 separated heretofore. This group includes those families of 

 the Specialized Frenulum-conservers in which the base of the 

 second branch of media (vein Vj) tends to migrate towards 

 radius ; or in other words, those Specialized Frenulum-con- 

 servers in which the tendency is to form a three branched 

 cubitus. (See p. 76 for a discussion ol the importance of this 

 character.) 



G. Moths resembling Noctuids in their general appearance, 

 having heavy, strong wings ; but readily distinguished from 

 that family b}' the direction of the migration of the base of 

 vein V,. In this family there seems to be but little if any 

 tendency to specialization of the humeral angle of the hind 

 wings. (Compare with the Geometridae below.) 



Family Notodontid.^^. 



GG. Of this group I know only a single species, Brephos 

 iiifans. I therefore hesitate to characterize it. I believe, how- 

 ever, that this represents its natural position. 



Family Brephid^. 



