AQUATIC INSECTS IN NEW YORK STATE 



475 



ii suitable place to pass the pupa state. Walsh gives an account 

 of the crawling of the mature larvae to the top of a chimney 

 of a small house by the Mississippi river. 



When the last larval skin is shed, the pupa' is very light brown 

 or nearly white, but gradually becomes darker up to the end 

 of the period. The pupa very much resembles the adult in ex- 

 ternal structure, specially as regards the antennae, tarsal seg- 

 ments, wing pads, and absence of lateral filaments, spongy tufts 

 ^nd prolegS'. There is great variation in the appearance of the 

 ■warty prominences left by the bases of the filaments. 



The len^h of the pupal life was determined by daily observa- 

 tion of specimens which had just crawled from the water to 

 :find a nest for the pupal life. The transformations of 25 speci- 

 mens were thus noted. It was found that the time spent in 

 the nest before the larval skin is shed varies from about one 

 ■day to as much as two weeks. The time from this last molt 

 till the adult emerges, or the actual life of the pupa, is not so 

 Tariable, as-thei table will show. 



No of larvae 

 observed 



Date of molting larval 

 Bkin 



Date of emerging as 

 adults 



Days in pupal 

 life 



4 



5 



12 



2 



1 

 1 



May 29 

 May 28 

 May 29 

 June 7 

 June 9 

 June 12 



June 8 

 June 4 

 Juue 7 

 Jnne 14 

 June 23 

 Juue 26 



10 



7 



9 



7 



14 



14 



It will be noticed from the table that the length of life in 

 tMs state varies from sfeven to 14 days with an' average of nine 

 ■days in the specimens observed. Many (perhaps 10 or 15) others, 

 "which I observed, died during that state. This was probably 

 partly due to the fact that they were handled too much, or 

 Tjecame too dry in the cages where they were kept, but I have 

 often found dead pupae UTBdac stones on banks of streams. 



The a;dult8 are perhaps as good fliers as Chauliodes, and both 

 of these will make longer flight® than Sialis; both are often 

 tound at great distance from streams, while Sialis seldom 



