256 THE CANADIAN ENTOMOLOGIST. 



of that season's brood and the main emergence of the year took J 

 place in late May. This probably shows that the males die first, 

 the females surviving longer in order to complete oviposition." 



"The following field notes were made at Northampton (Fish- 

 house) in Fulton County, New York State, from May 25 to 21;, 4 

 1914, where adults were reared from nymphs taken in small tem- 

 porary pools left by the vernal overflow of the Sacandaga River:" 



'' Siphlonisca was first noted as a subimago in a tent-trap set 

 on May 25th. The contents of the trap were examined on the 

 following day and the catch included a subimago of 5. cBrodromia. 

 After determining the habitat of the nymph, it was a simple matter 

 to obtain the later stages. The nymphs crawl up the rush stems 

 in order to emerge, usually leaving the cast skins three to four inches 

 above the water level. Occasionally the cast skins are found on 

 the upper surface of flat leaves." 



"The nymphs of Bcetisca obesa, Siphlurus minis, and Siph- 

 lonisca (Efodromia occurred together in company with a great 

 abundance of other mayfly nymphs of smaller and less conspicuous 

 habit. The pools evaporated rapidly, and on May 27th, only two 

 days after the first observations were made, had dwindled to one- 

 half of their former size. The water became very warm and tepid 

 towards midday, and this was more apparent each day as the 

 amount of water decreased and the abundant animal life became 

 more concentrated." 



"Nymphs of the various mayflies were isolated and reared 

 through to the imago. The most abundant species in the pools, 

 with the exception of some of the smaller and less conspicuous 

 species, was Bcetisca obesa. In an area of a few square yards, 

 there were hundreds of cast skins of the species adhering to the 

 rush stems long after the subimagoes had flown away. The cast 

 skins of Si phlonisca were almost as common, on some of the rush 

 stems there being as many as four of the cast skins on a single stalk, 

 arranged end to end and crowding one another. Bcetisca was found 

 to emerge at midday or slightly after, specimens being observed at 

 2 p.m. Siphlonisca came out at all hours of the day, but more 

 abundantlv in the late forenoon." i 



