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 m y i a 

 aa Abdominal segments without these cushions 



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

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



figs. 1 and 4 ( Group C er a t o p o g on) 



hi) "Not as above 



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

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



pl.l9, Iig.9 ( Crroiip T any p us) 



cc Not with all the above characters 



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

 tions 

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

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

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



26. W u 1 p i e 1 1 a 

 re 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. Metriocnemus 

 (Id 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.lO 

 f With two anal blood gills, pl.3(>, figs. 1, 2, 3 



25. 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, pi. 20, figs. 5, 8 42. Tanytarsus 



ee Antennae short 



f Larvae usually blood red ; eleventh body segment with two 

 pau'S of blood gills, pi. 15, fig.4. .38. C h i r o n o m u s (pt.) 

 ff Larvae greenish, yellowish, or whitish 



g The maxiliary palpus usually noticeably longer than broad. 

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



and 16 38. C h i r o n o m u s (pt. ) 



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



fi Full-grown larva not over 6 mm. long, green or bluish- 

 green in color. Anterior abdominal segments of greater 

 diameter than the posterior ones. Mandibles often 

 transversely wrinkled ; the anterior prolegs usually with 

 pectinate setae 



■ ' " s 



f 39. C r i c o t o p u s 

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



