MAY FLIES AND^MIDGES OF NEW YORK 265 



Imago. Resembles Cricotopus and Camptocladius. 

 The fore metatarsus is shorter than the tibia; the legs are not 

 black and white annulate, but nearly uniform in color, either 

 dark or light, in the latter case at most with only dark articula- 

 tions. Wings bare, R^ enters the costa beyond the mid length of 

 the wing; R^^l^ straight or only slightly bent, reaching the end 

 of the costa; crossvein at or even before the mid-length of the 

 wing; the forking of the cubitus usually noticeably distad of the 

 crossvein ; the posterior branch straight or gently curved. Geni- 

 talia of the type shown on pl.33, fig.l, thus resembling Cricoto- 

 pus (fig.2). The species usually small, though occasionally of 

 moderate size. In other respects like Chironomus. It will 

 be noted that it does not differ structurally from Cricotopus, 

 differing only in color characters. 



KEY TO SPECIES OF ORTHOCLADIUS 



Larvae 

 a Mandible slender with sharp apex ; antennae slender ; margin of labium 



irregular, pi. 24, fig.l2 5. f 1 a v u s n. sp. 



aa Mandible rather stout ; margin of labium with regular teeth 



h First laterals of the labium notched on the outer margin ; mandible 



with lateral surface wrinkled 15. f u g a x n. sp. 



&& First laterals with rounded margins 



c Labium on the lower surface with two converging folds, pl.25, fig.l4 



7. sordidellus 

 ce Labium without these folds, pl.24, fig.21 8. nivoriundus 



Pupae 

 a Posterior margin of each abdominal segment with a row of long stout 



setae, pl.24, figs. 15 and 16 5. f 1 a v u s n. sp. 



aa The segments without these setae 



b Dorsal surface of each segment nearly uniformly covered with minute 

 spines and four pairs of setae; respiratory organ with enlarged 



apical end, pl.24, figs. 22, 23, 24 8. nivoriundus 



bJ) Dorsal surface with several transverse patches of minute spines 



c The patch covering the center of the disk of each segment largest, 



pl.25, figs. 7 and 11 15. f u g a x n. sp. 



cc The middle band consists of two irregular rows of short stout spines 



7. sordidellus 



Imagines 



a Yellowish species. (The females, and the species with brown abdomens, 



should be sought for in the next section also. ) 



h Large species 6 mm. in length ; yellow ; thorax with three dark yellow 



or brown stripes ; abdomen with two brown spots on each segment ; 



male 1. par 



