MAY FLIES AND MIDGES OP 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. Psamathiomyia 

 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 Ceratopogort) 



&& Not as above 



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

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



pl.19, fig.9 (Group T any pus) 



cc Not with all the above characters 



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

 tions 



e 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. Wulpiella 

 ce Eyes not on anterior angles of head 



f With blood gills on venter of eleventh segment 



31. Hydrobaenus 

 ff With blood gills only at end of twelfth segment 



44. Metriocnemus 

 da Caudal tufts on small rounded papillae 



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



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

 f With two anal blood gills, pl.36, figs. 1, 2, 3 



25. Corynoneura (lemna) 



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, pl.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, pL23, figs. 3 



and 16 38. Chironomus (pt. ) 



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



h 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 f 39. Cricotopus 



\ 41. Orthocladius 



