MAY FLIES AND MIDGES OF NEW YORK 87 



KEYS TO GENERA OF THE CHIRONOMIDAE 



Larvae 



a Abdomen with prominent rounded elevations or cushions, with rows of 

 teeth on the inferior (anterior) angles of the segments 



13. P s a m a t h i o m y i a 

 aa Abdominal segments without these cushions 



b Aquatic footless snake-like larva, or terrestrial larva with thoracic 

 and anal feet, and many setae and bristles on body segments, pi. 17, 



figs. 1 and 4 ( Group C e r a t o p o g o n) 



hb Not as above 



c With retractile antennae, the hitter often quite long, long stilt-like 

 legs, the caudal tufts of hair mounted on cylindrical processes, 



pl.l9, fig.9 ( Group T any pu s) 



cc Not with all the above characters 



d With the two caudal hair tufts mounted on cylindrical projec- 

 tions 

 r With six seta-like processes on each of the caudal projections, 

 three long aud three short. Eyes prominent, round, on ante- 

 rior angles of the liead, pi. 34, figs. 21, 22, 23 (European) 



26. W u 1 p i e 1 1 a 

 cc Eyes not on anterior angles of head 



f With blood gills on venter of eleventh segment 



31. H y d r b a e n u s 

 ff With blood gills only at end of twelfth segment 



44. M e t r i o c n e m u s 

 dd Caudal tufts on small rounded papillae 



e Antennae elongate, at least one half and often as long or longer 

 than the head ; compare also pi. 20, fig. 10 

 / With two anal blood gills, pl.3G, figs. 1, 2, 3 



2.5. C o r y n o n e u r a ( 1 e m n a ) 

 ff With four anal blood gills ; antennae mounted on basal promi- 

 nence, pl.26, figs. 5, 8. 42. Tanytarsus 



ee Antennae short 



f Larvae usually blood red ; eleventh body segment with two 

 pairs of blood gills, pi. 15, fig.4. .38. Chironomus (pt.) 

 ff Larvae greenish, yellowish, or whitish 



g The maxiiiary palpus usually noticeably longer than broad. 

 Larva in pools, pond water, or slow streams, pi. 23, figs. 3 



and IG 38. Chironomus (pt.) 



gg Palpus about as long as broad, pl.24, figs. 5, 12, 20 



h Full-grown larva not over G mm. long, green or bluish- 

 gi-een in color. Anterior abdominal segments of greater 

 diameter than the posterior ones. Mandibles often 

 transversely wrinkled ; the anterior prolegs usually with 

 pectinate setae [39. Cricotopus 



41. O r t h o c 1 a d i u s 



y 



