AQUATIC INSECTS IN NEW YORK STATE 355 



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



1.5 to 2uiin. Compare here also b r a c t e a t u ra (male). 



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



Thorax brownish black; legs usually pale; tip of tarsi not 



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



8 Thorax with silvery white pubescence; legs brownish black, 



covered with whitish hairs. A small variety (less than 

 2mm long), from New Mexico has been named o c c i d e n - 



tale 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) 



Females, eyes sepai'ated '. (20). 



10 " Mesonotum Avholly velvet black; gray spot on siides of the 



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



Length 1.5mm." b r a c t e a t u m 



Metanotum striped, or with grayish or metallic reflections (11) 



11 Dorsum of thorax with one or more longitudinal stripes (12> 



Dorsum unstriped (14) 



12 Thorax Avith four longitudinal stripes; posterior margin 



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



quadrivittatumi 

 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) 



13a "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. New Mexico virgatum 



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



13b Mesonotum Avith two narrow gray stripes (sometimes quite 

 indistinct) on a velvet black ground, in which thei-e are 

 scattered golden hairs v i 1 1 a t u m 



" Mesonotum marked with a narrow median and slightly 



wider lateral black vittae." Length 2.5mm. ISIissouri. .g 1 a u c u ni 



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 ni 



Abdomen 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 n> 

 Thorax fuscous and cinereous polIino.se; the humeri pallid, 

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

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



