34 



Nasia'srlnia poitdvatitJta Ramb. 



The nymph of this species was doubtfully referred by Grar- 

 man ('90, p. 178) to Epia'scliua heros. It differs from all Amer- 

 ican seschnids hitherto described in the possession of dorsal 

 hooks on the 8th and 9th abdominal segments, having the form 

 of a median carina terminating in a posteriorly projecting tooth. 

 In aspect and habits this interesting nymph is very peculiar. It 

 is rough, blackish, and very sluggish, and clings to dead branches, 

 roots, or driftwood in quiet water. Doubtless it depends, as 

 Mr. Garman suggests, on its obscure color and slow movements 

 for escaping detection. Examples were taken by Mr. Hart in 

 April and May on branches in dead water and along the banks 

 of a slow-flowing stream near ITrbana, and also a very young 

 one in August in a muddy remnant of a temporary stream in 

 Perry county, in southern Illinois. Mr. Clarman's specimens 

 were from a muddy slough of the Mississippi near Quincy. Out- 

 side of Illinois the imago has hitherto been reported only from 

 New York (June), Louisiana, and Texas. Mr. Needham saw 

 one taken at Wellesley, Mass. In Illinois it was taken by Walsh 

 at Rock Island ; and we have specimens from Urbana, and also 

 from Cobden in southern Illinois. An imago was found float- 

 ing May 20 in a narrow passage where nymphs were at the time 

 quite numerous on dead branches lying in the water. From 

 these nymphs adults were obtained up to June 10. Our other 

 imagos were taken June 11 and 16. 



In addition to the presence of dorsal hooks, as already stated, 

 the nymph differs further from E. heros, as described by Cabot 

 ('81, p. 30, PI. I., Fig. 3), in the presence of two pairs of tuber- 

 cles upon the head, in the absence of lateral spines on the 4th 

 abdominal segment, and in that the two processes above each 

 front coxa are of equal length. 



The nymph measures 48 mm.: abdomen, 34 mm.; hind 

 femur, 6 mm.; width of abdomen, 8.5 mm., of head, 9 mm. 



The median labial lobe is prominent, cleft, without teeth 

 on each side of the cleft. The lateral lobes are squarely trun- 

 cate, with the outer angle rounded, their sides parallel beyond 



