AQUATIC INSECTS IN THE ADIRONDACKS 4O9 



to come into the hatchery was the fly, R o e deri o des juncta. In 

 addition to these forms, and the green stone fly, Chloroperla bi- 

 lineata Say, which doubtless belongs with them in its season, there 

 occurred in the hatchery a large number of Diptera of various sorts, and 

 the spongilla flies, hitherto accounted so rare. Fresh-water sponges 

 from the lake above invade the pipes, and the larvae of these flies come 

 in with the sponges on which they live. 



On June 19 we collected the contents of one of the supply troughs in 

 the hatchery. It contained more than 125 little fresh -water sponges, 

 averaging the size of peas, from which were picked seven spongilla fly 

 larvae, nine amphipods (undetermined), one entomostracan, Epis- 

 chura lacustris Forbes, about a dozen each of two species of May 

 flies, Heptagenia pulchella Walsh and Ephemerella ex- 

 crucians Walsh, a large number of black fly larvae, a few H y d r o p- 

 s y c h e larvae, a few gnat larvae and a number of colonies of rotifers. 



Some of the multitudinous gnats in the windows were of the same 

 species that I bred from larvae taken from '' skin algae " scraped from 

 the races outside. Horseflies (Tabanidae) were also conspicuous occu- 

 pants of the windows, but I did not find their immature stages in the 

 hatchery. Possibly these may have come in through open doors and 

 windows, being so active and so abundant outside. The handsome 

 longicorn beetle, Leptura canadensis Fabr., which was not 

 uncommon in the windows during the latter half of the session, certainly 

 entered in this way. 



A small number of. specimens representing a new genus and species of 

 Stratiomyiidae (describedinpart 3,p. 585 asZabrac hia polita Coq.) 

 were picked from the hatchery ceiling, whfle gathering spongilla flies. 



Red hydras were exceedingly abundant in Little Clear creek during 

 the first half of our session, insomuch that they fairly covered every 

 trailing stem and leaf in the current, and occupied every available sup- 

 port, even to the backs of the dragon fly and May fly nymphs, one of which 

 would often bear half a dozen or more of them. Then they gradually 

 disappeared, till in August hardly a hydra was to be found. A single 

 blade of Sparganium brought in in June for some eggs of B a s i a e s c h n a 

 Janata which had been laid in it, bore hundreds of hydras profusely 

 budding, and all of a very distinct red color. An observant employee 

 of the hatchery, Milo Otis, who attends to feeding the fry, informed me that 

 at certain times the water flowing through the ponds is tinged with red 

 from the hydras floating in it, and that at such times the young trout sub- 

 sist on these, and refuse to eat other food. It would be interesting to 



