MAY FLIES AND MIDGES OF NEW YORK 197 



oo Abdomen brown, posterior margins of 

 anterior segments widely yellowish, with 

 cinereous bloom ; crossvein indistinctly 

 clouded ; fore metatarsus over two 

 thirds longer than its tibia ; length 3 to 

 4 mm. (Illinois and New York) 



57. s i m i 1 i s n. sp. 

 jj Crossvein clouded with brown 



k Brownish species with strongly defined wing veins ; 



length 6 mm 58. r e d e u n s 



kk Not such species 



I Fore tibiae blackish ; in mature specimens the 

 dorsal stripes and metanotum black ; fore meta- 

 tarsus 1.5 times longer than its tibia ; length 



7 to 9mm 49. viridicollis 



II Fore tibiae pale 



m Large species 10 or 12 mm. in length ; fore 

 metatarsus 1.25 times the length of its tibia ; 

 male fore tarsi long haired 

 n With dusky thoracic stripes 



59. p 1 u m o s u s 

 nn With reddish thoracic stripes 



59a. ferrugineovittatua 

 mm Smaller species 



n Dorsum of thorax whitish or pale cinereous 



or greenish, with reddish stripes 

 o Fore metatarsus over 1.33 times its tibia 



in length ; male fore tarsi bare 

 p Metanotum reddish or brownish, fore 

 metatarsus 1.6 times its tibia ; length 



5 to 7 mm GO. decorus 



pp Metanotum blackish ; fore metatarsus 

 less than 1.5 times its tibia in length 



60a. d o r s a 1 i s 



oo Fore metatarsus about 1.2 times its tibia 

 in length ; male fore tarsi hairy ; abdom- 

 inal fasciae reddish, incisures whitish ; 

 length 7.5 mm. 61. stigmaterus 

 nn Dorsum of thorax with brown or cinereous 



stripes 



o Length 3 or 4 mm. ; fore metatarsus about 

 two thirds longer than its tibia 



57. s i m i 1 i s 

 oo Larger species 



p Fore tarsi of male bare 



q Male claspers slender ; fore metatar- 

 sus about 1.5 times its tibia in 

 length ; dorsum of thorax yellow 

 with brownish gray stripes ; head 

 blackish ; length 8 mm. 



62. cristatus 



