AQUATIC INSECTS IN NEW YORK STATE 475 
a 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 
and prolegs. There is great variation in the appearance of the 
‘warty prominences left by the bases of the filaments. 
The length 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 
variable, as the table will show. 
No. of larvae Date of molting larval Date of emerging as Days in pupal 
observed ; skin | adults life 
4 May 29 June 8 10 
5 May 28 June 4 7 
12 May 29 June 7 9 
2 June 7 June 14 7 
a June 9 June 23 14 
1 June 12 June 26 14 
It will be noticed from the table that the length of life in 
this state varies from seven 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 
became too dry in the cages where they were kept, but I have 
often found dead pupae under stones on banks of streams. 
The adults are perhaps as good fliers as Chauliodes, and both 
of these will make longer flights than Sialis; both are often 
found at great distance from streams, while Sialis seldom 
