AQUATIC INSECTS IN NEW YORK STATE 457 



leugith of the pupal stage lias not yet been exactly determined, 

 but the period is probably not longer than two weeks. Walsh 

 and ^yeed both mention C. r a s t r i c o r n i s , as being found 

 under bark of the upper side of logs floating in water. They 

 were doubtless there to pupate. Weed speaks of the pupa stage 

 of that species as lasting eight days in one case and 14 days in 

 another case. H. L. Moody [1878] notes that a specimen of 

 C. p e c t i n i c o r n i s spent 12 days in the pupa stage. 



The pupae are quiescent but can crawl when disturbed. The 

 color is at first light brown but becomes dark before the emer- 

 gence of the adult insect. As in the case of Sialis and Coi\ydalis, 

 the pupae very much resemble the adults in many points of 

 external structure. Walsh says of pupae of C. r a s t r i - 

 cornis, that at least the female has two robust obtuse ab- 

 dominal appendages, about 2mm long, confluent at base; and 

 an inferior process of two similar ones, connate throughout. 



The adults are better fliers than Sialis, but are still very awk- 

 ward and are not difiicult to catch. They are chiefly crepus- 

 cular, but often fly in the late morning, and are easily frightened 

 from their diurnal hiding places along a wooded stream. Speci- 

 mens taken to cages have all died in a very short time, and it 

 is probable that the life in the winged state is only a few days. 

 They have not been known to take food in this state. 



Adults of C. s e r r i c r n i s have been collected at Ithaca 

 from June 9 to 18 in various years. 



KEV TO SPECIES OF CHAILIODES 



a Wings black or browu with white markiugs 



b A contiuuous, broad, somewhat arcuate white 

 band extending across the middle of each wing 

 almost attaining the hind margin of each; an- 

 tennae serrate in the female, flabellate in the 



male 1 f a s c i a t u s 



bh An irregular band of white spots, generally 

 broadest in front, extending across the middle 

 of each front wing, on the hind wing repre- 

 sented by only a few minute dots which may 

 be wanting; antennae more or less serrate in 

 both sexes [pi. .52] 2 s e r r i c o r n i s 



