on the Ephemeride. 67 
oblongam vel triangulam apud latera segmenti singuli 
utrinque relinquit; striga ipsa segmentorumque apici- 
bus fuscis.”” (Walsh.) 
Long. corp. ¢ 17-21, 2? 21-29; set. ¢ 42-51, subim. 
18; set. 9 20, subim. 18-19; al. ¢ 17-20, 9 21-23 mm. 
Hab.—Arctic America, to New Orleans; in lakes and 
rivers. 
The Hexagenie are said to appear in suitable localities 
in astounding profusion. The late Mr. Walsh says he 
has seen shrubs broken down by the accumulated masses 
of one species upon them! ‘The name of the shrub, and 
how many thousand specimens of the Hexagenia in ques- 
tion go to the pound, are unfortunately omitted from his 
observations. 
Genus HurnypLocia, nov. gen. 
(Alee anticee partes, Pl. I. fig. 8, 8a.) 
Palingenia, p., Hag. 1861. 
Imago ¢. Ala quatuor. Seta tres, longs, sub- 
eequales. 
Huthyplocia Hecuba. 
Palingenia Hecuba, Hag. 1861. 
Imago, v.s. s. ?. ‘‘ Capite nigro-fusco ; prothoraco 
fusco, polito ; coxis luteis; alis magnis opacis, cervino- 
tinctis, costas versus obcuratioribus, nervis griseis. Ab- 
domen supra nigro-fuscum, subtus lutescens;  setis 
_ saturate fumatis.” (Hag.) 
Long. corp. 22, exp. al. 78 mm. 
Hab.—Vera Cruz (Sallé) ; Veragua. 
There is a specimen of this insect in Mr. M’Lachlan’s 
collection, and another (the type) in that of Baron De 
Selys Longchamps. The legs are lost, and the colours 
are so faded, that I have preferred citing the old de- 
scription to redescribing the species. In what Dr. Hagen 
suspects to be the male, the undivided eyes are almost 
contiguous, the median seta is very long, and the an- 
terior legs are long and feeble. 
FQ 
