84 Bulletin 64. 



have become sickle- shaped. The genital plate has nearly the 

 rounded form of C interminellus and this species is probably most 

 closely related to that form. 



The Luteolellus Division : 



As before stated, C. luteolellus is placed in this division, but is 

 treated of first, because it is the most generalized form of the 

 species studied. 



Subdivision I. 



The Decorelhis Group.— Vl^ies I., II., VI., XII., XIII., Fig- 

 ures 6-9. 



By their larger size and their uniform dull yellow color these 

 species are seen to be more specialized forms than have descended 

 from C. luteolelhis, or allied species, and not from the dark colored 

 Caliginosellus Group. In fact all the species of this division 

 trace back to C. luteolellus. 



6. Crambus decorellus. This species has a broad generalized 

 wing. The antennae are somewhat specialized, the joints being 

 shorter and broader than in C luteolellus. The valves are nearly 

 triangular which is a marked departure from the primitive type. 

 The harpe is greatly reduced and strongly curved. The uncus 

 and the lower limb are well developed, probably because the harpe 

 is so reduced and twisted as to be of little use. The scaphium is 

 long and deep. 



7. Crambus teterrellus. In this species the fore wing has been 

 narrowed. The male antennae are highly specialized. The valve 

 has about the same form as in the preceding species, while the 

 harpe has become more specialized by reduction in size and by the 

 development of a double recurved hook. In consequence of the 

 greater efficiency of the harpe the uncus has been greatly reduced. 

 The genital plate has a slight tendency toward irregularity in 

 outline. 



8. Crambus ruricolellus . This species and C. vulgivagellus 

 represent a line of development where the harpe has been greatly 

 reduced and is therefore inefficient ; the uncus has suffered but 

 little reduction. The valves are more flattened than in the two 

 preceding species. The w^ing is not .so specialized as in C. teterrel- 

 lus, but is more specialized than in C. decorellus. The labial palpi 

 are longer proportionally than in C. teterrellus and shorter than 



