AQUATIC INSECrrS INNEfW YORK STATE 



227 



This is the common and perhaps the only species in New York 

 State. The above account of the habits of the genus has been 

 written with this species in mind. It is as yet recorded from 

 but three localities in the State, but it will doubtless be found 

 in many other places when proper search is made for it. Its 

 nymph has not been described, but in 1880 Dr Hagen drew char- 

 acters distinctive of the genus from nymphs which he referred to 

 H. californica, H. americana, H. titia and an 

 undetermined species from Brazil,^ and Oalvert^ and Williamson* 

 have used these characters in keys to American nymphs. 



Nymph. Length of body 17mm; antennae 4mm additional; 

 gills 7mm additional. Color greenish or brownish, paler. on the 

 sutures, on legs and on margins of gill 

 plates, but without distinct color pattern. 

 Occasional specimens show faint indic;x- 

 tions of darker transverse bands on the 

 tibiae and gill plates. 



Head flat above, with rounded eyes set 

 well forward, with hind angles obtuse and 

 having a much lees distinct superior tooth 

 than that of Oalopteryx. Antennae long, 

 inserted into large frontal prominences, 

 somewhat shorter than the head is wide, 

 the first segment longer than the following 

 six, which rapidly and successively decrease 

 in length and thickness. Labium long, the 

 hinge extending posteriorly between the 

 bases of the middle legs; mentum suddenly 

 and greatly dilated in its apical half, its 



median lobe divided into two lobes by a ^,^ , Antenna, and end of 



median cleft, which is rounded basally and abdomen showing lateral 



' ^ spines and glU plates, of 



extends barely below the level of the bases J^™?^, °* .^^'*^''"'> 

 of the lateral lobes of the labium; the distal 



end of the cleft is closed by the apposition of the two divisions 

 of the median lobe; beside the cleft on either side is a single 

 small spinule. Each lateral lobe of the labium is straight on 

 its outer margin, with a moderately strong and arcuate movable 

 hook, just before the base of which on the superior margin are 

 three small spinules. The exposed portion of the inner margin 

 is strongly convex, and finely serrulate, and terminates after a 

 sigmoid curve, in a short, stout, strongly arcuate end hook; 



lEnt. Soc. Belgique, Compte Rendu, 23:65. 



2 Am. Ent. Soc. Trans. 20:225. 



3 Dragon Flies of Indiana, p.247. 



