55 



flattened, bearing eight strongly chitinized, flattened, hooked setae ; and 

 usually having similar but smaller setae on the anal rise. Exceptions 

 to this latter character are found in the genus Polychrosis, and in 

 Hxartema fcrrifcraninn, which does not agree with the remainder of 

 the genus in this respect. The group is further characterized by the 

 presence of a well-developed row of spines on the ninth abdominal 

 segment in all the males examined and in nearly all of the females, the 

 exceptions being in the genus Exartema, where the spines were smaller 

 and fewer in number. In most genera this row of spines has several 

 additional spines on each side, usually near the meson. The only 

 other species of the superfamily which resemble the members of this 

 group are the species of Archips in group (b), but these have no setae 

 on the anal rise, and very seldom have spines present on the ninth 

 abdominal segment. Hxartema ferriferanum is the only species among 

 those examined which might be confused, as the row of spines on 

 the ninth segment of the female is not well developed, while the males 

 of Archips cerasivorana sometimes have a few spines present. This 

 particular species of Exartema, however, has a prominent cephalic 

 projection, ending in a point, directed ventrad, while the species of 

 Archips are blunt at the cephalic end, and the bodies are usually larger 

 and prominently enlarged in the region of the thorax. The antennae 

 show marked sexual differences, being much longer in the males. The 

 rows of spines on the dorsum of the abdominal segments also vary in 

 tl)e sexes, the caudal row of segment eight being poorly developed or 

 lacking in many females, though well developed in the males. The 

 row on the ninth segment is much better developed in the males. The 

 genus Polychrosis shows a peculiar development of the spiracles. 

 Instead of the small, produced tubular spiracles common to the Tortri- 

 coidea it appears to have them very much enlarged. This prominent 

 enlargement around the spiracle has a deeply concave surface, and the 

 very small tubular spiracle in the center is about one sixth of its width. 

 A similar condition, but not so well developed, is found in Exartema 

 sciotoaniim. The maxillary palpi are well developed and reach the 

 proximo-lateral angles of the maxillae in Olethreutes (b) and Poly- 

 chrosis, but in Episimus, Olethreutes (a), and Exartema they are not 

 well developed. The genera of Olethreutidae may be separated as 

 follows : 



a. Tenth abdominal segment with spines, usually three or four rows 



closely approximated, seldom with a single row. 



b. Long chitinized setae present on the anal rise, usually slightly 



shorter and narrower than those of the cremaster. 



c. With two setae on each side of the anal rise, very similar to those 



on the cremaster Episimus Walsingham. 



