MAY FLIES AND MIDGES OF NEW YORK 67 



4. Hydroptila hamata n. sp. 



The dorsal plate in the male is small, broadest in the middle, 

 apex excised. Beneath it there is a small rounded penis-cover. 

 The appendages are narrow, finger-shaped, aristate and widely 

 divergent. Two strong hooks visible at the posterior margin of 

 the last ventral plate or segment. The penis is very slender, 

 curved at the apex and accompanied by a slender sheath of equal 

 length. Ventral lamina very long; in lateral outline somewhat 

 club-shaped, but lower margins oblique and minutely serrate. 



This species is certainly near to the European f e m o r a 1 i s , 

 but it differs especially in the form of the dorsal plate which in 

 femoralis is not notched and is boat-shaped in outline. 



5. Hydroptila perdita n. sp. 



Antennae about 31-jointed in the <J. The dorsal plate is large, 

 rounded posteriorly, gradually becoming wider, the margins 

 slightly retracted at the base, a small hollow looking patch near 

 the apex. The inferior appendages subparallel blades, twisted 

 outwards at the apex, which is obscurely bifid; scattered 

 spinous hairs, particularly on external (superior) margin. Penis 

 broad towards the base; in the exserted part tapering to a 

 point, below which is a very strong curved acute process standing 

 out strongly from the stem. Ventral lamina small. 



ITHYTRICHIA 



The typical forms of this genus are rather robust-looking 

 insects bearing considerable resemblance to the species of 

 Hydroptila, but they are at once distinguishable on account 

 of their distinct ocelli and the absence of the elevated lobes on 

 the posterior part of the head. 



6. Ithytrichia clavata n. sp. 



In the c? the antennae are about 24-jointed. The appendages 

 may be described as follows: There appears to be a transparent 

 dorsal plate with outer margin nearly semicircular in outline, 

 but the plate is very difficult to separate from the other parts. 

 There are very large side pieces of subtriangular form in the 

 lateral aspect, blade-like if viewed from above, the apex down- 

 turned and outturned rather acute and blackened at the extreme 



