258 THE CANADIAN ENTOMOLOGIST. 



"By May 28th, the water in the temporary pools was entirely 

 evaporated, but the larger mayfly nymphs had matured so rapidly 

 or were timed so opportunely that not a single nymph was left. 

 An immense number of the nymphs of smaller species and the 

 plankton (a. large red ostracod in great abundance; Daphnia and a 

 great number of other Entomostraca; Planarians of two species, 

 one being a small light green form; Mollusca, (Aplexa Jiypnorumf 

 Segmentina, Pisidiiim sp.; etc.) of the pools were exposed and 

 perished. The stench of their decaying bodies attracted many 

 carrion-lo\'ing insects such as Liicilia. Silpha inccqiialis, etc." 



Siphloplecton gen. nov. 



Caudal setae two, middle one rudimentary. Fore tarsus of 

 male with 2nd segment about equal to 1st, the 3rd slightly longer 

 than 1st, the 4th slightly shorter than 1st, the 5th about half the 

 length of 1st. Female fore tarsi 1, 2 (3 and 5) equal, 4. Hind 

 tarsi of both m.ale and female in order of decreasing lengths 1, 

 (2 and 5) equal, 3, 4. Hind tibia shorter than its tarsus. Claws 

 of each tarsus unlike. Wing without dependent intercalaries from 

 the 1st anal, and cubitus 2 strongly curved at base. Penes lobes 

 rounded with slight indentations. Sternum of ninth abdominal 

 segment of female produced slightly and entire at tip. 



Nymph with hind claws hooked and claw-like, but fore claws 

 flattened and bifld. Labial palpus with but two segments. Gills 

 double on segments 1, 2, and 3. 



Type species — Siphlunis flexns Clemens (Can. Ent.. 1913, 

 vol. XLV, p. 338), Go Home Bay, Georgian Bay, Ont. 



Besides the Georgian Bay material I have seen specimens 

 from Douglas Lake, Michigan,, Nov. 25, 1904, from Walnut Lake, 

 Mich., April 12. 1906, and from the Michigan Agricultural 

 College campus, East Lansing, Mich., Jul}^ 15, 1910. 



References. 



1868 — Eaton, A. E.: An outline of a re-arrangement of the 

 genera of Ephemerida?. Ent. Mag. V, p. 89. 



1870 — Eaton, A. E.: On some new British species of Ephe- 

 meridai. Trans. Ent. Soc, London, 1870, p. 7. 



