MAY FLIES AND MIDGES OF NEW YORK 



187 



Pupa. The pupa usually remains within the tube constructed 

 by the larva, but is capable of swimming freely like a frog larva. 

 It is provided with a pair of much branched thoracic filaments, 

 and its caudal segment is fringed with long matted hairs or 

 filaments forming a paddle (pl.23, fig.9 f). 



Imago. The genus Chironomus as restricted by Van der 

 Wulp (1874 and 1877, p.245) is defined by him in the latter work 

 as follows : Face usually hairy, lengthened downward snout-like ; 

 proboscis short, palpi bent, 4-jointed, the last joint elongated. 

 Antennae filiform, in the male 14-jointed, the first joint short, 

 disk-like, the second cylindrical, the following rounded, closely 

 sessile, the end joint very long and slender, all long and densely 

 plumose; toward the tip the hairs become gradually shorter; in 

 the female the antennae are much shorter, 7-jointed ; the first joint 

 short, disk-like, the second cylindrical, the following four oval, 

 sparsely haired, the last joint somewhat elongate. The eyes on 

 their mesal margin deeply emarginate, ocelli wanting: Thorax 

 highly arched, more or less projecting over the head, flattened in 

 front of the scutellum, pectus very prominent, scutellum small; 

 metanotum well-developed; the markings of the thorax, if not 

 unicolored, consist of three, usually wide longitudinal stripes, of 

 which the median is posteriorly and the two laterals anteriorly 

 abbreviated; sometimes the median stripe is divided longitudin- 

 ally by a fine line, which continues to the scutellum. Abdomen 

 cylindrical, in the male sometimes flattened, the last or anal seg- 

 ment distinctly separated from the preceding, longer than broad, 

 the genitalia projecting tong-like, the claspers filiform or leaf -like. 

 Legs long and slender, particularly the fore pair, of which the 

 tibiae are frequently very short, while the fore metatarsus is 

 always longer than its tibia ; the fore tarsi of the male are some- 

 times peculiarly haired; the tarsal claws and pulvilli upon all 

 the feet are small but distinct. The wings are bare, in the male 

 often shorter than the abdomen, the anal angle always present, 

 sometimes strongly projecting; subcostal vein delicate but dis- 

 tinct, as is also R x which enters the costa beyond the middle of 

 the wing ; K^ emerges from the small crossvein, at its extremity 

 usually slightly curved downward, entering the margin not far 

 from the apex of the wing; the media is unbranched and joins 



