AQUATIC INSECTS IN NEW YORK STATE 355 



7 Thorax velvety black; legs reddish with black tarsi. Length 

 1.5 to 2ium. Compare here also b r a c t e a t u m (male), 



" with legs wholly brown." m e r i d i o u a 1 e 



Thorax brownish black; legs usually pale; tip of tarsi m)t 



black. Length from 2 to 4mm p e c u a r u m 



S Thorax with silvery white pubescence; legs brownish black, 

 covered with whitish hairs. A small variety ,(les» than 

 2mm long), from New Mexico ha» been named occiden- 

 tal e Town. (q. V.) m e r i d i o n a 1 e 



Thorax with yellow hairs; legs reddish brown, covered with 



yellow hair; tip of tarsi blackish p e c u a r u m 



9 Males, eyes contiguous (10) 



-fi Females, eyes separated (20) 



10 " Mesonotum wholly velvet black; gray spot on sides of the 

 second, fifth, sixth, and seventh segments of abdomen. 



Length 1..5mm." b r a c t e a t u m 



^ ^Nletanotum stiiped, or with grayish or metallic reflections (11) 



C' 11 Dorsum of thorax with one or more longitudinal stripes (12) 



Dorsum unstriped (14) 



Jl 12 Thorax with four longitudinal stripes; posterior margin 

 white; abdomen black. Sex not given. Cuban species. . . . 



q u a d r i V i 1 1 a t u m 

 Thorax not so marked (13) 



13 Front and middle femora and tibiae wholly yellow; center of 



mesonotum with a black vitta, elsewhere gray. Length 



1.5mm. Colorado species g r i s e u m 



Femora and tibiae wholly or partly brown (13a) 



ISa " Femora and front tibiae yellow, their apices brown; mid- 

 dle tibiae brown, a yellow ring beyond the base, hind tibiae 

 brown, the extreme base yellowish. ]Mesonotum marked 

 with a narrow median and laterally with a very broad 

 velvet black fascia." Length 3mm. Xew Mexico virgatum 



Front femora brown, tibiae brown on apical part (13b> 



13b Mesonotum with two narrow gray stripes (sometimes quite 

 indistinct) on, a velvet black ground, in which there are 

 scattered golden hairs v i t t a t u m 



" Mesonotum marked with a narrow median and slightly 



wider lateral lilack vittae." Length 2.5mm. ^Missouri, .g 1 a u c u m 



14 Anterior femora yellow. Mexican species (15) 



Anterior femora black (17) 



15 Abdomen with the base of the second segment, and the sides 



of the third, fourth, and fifth yellowish white; tibiae fus- 

 cous black with yellow bases. Length 4mm m e x i c a n u m 



Al)domen black (16) 



16 Metallic bluish black species; middle portion of fore tibiae. 



base of middle and hind tibiae, base of first and second 

 joints of middle and hind tarsi, whitish. Length 2mm. .. 



m e t a 1 1 i c u m 

 Thorax fuscous and cinereous pollinose; the humeri ijallid. 

 fore coxae pale, middle and hind ones dark; femora pale at 

 the base, black at the tip; tibiae black. Length 3mm. .c i n e r e u m 



