356 NEW YORK STATE MUSEUM 



17 An oblique metallic streak extending inward from each 

 humeras; posterior part of the thorax metallic. Length 2 



to 2.5mm venustum 



Humeral spots not metallic (18) 



IS Anterior coxae yellow; long hair on femora and hind tibiae; 

 thorax velvet black with white pruinose margin (Green- 

 land) reptans 



Anterior coxae black (19) 



19 Thorax velvet black, with oblique cinereous humeral spots, 



and usually two tiny metallic spots between them. Length 



3 to 4mm p i c t i p e s 



Thorax velvety black with two very narrow gray stripes 

 and posterior mai'gin; hind tibiae usually yellow at the 

 base, hair on legs sparse v i 1 1 a t u m 



20 Thorax striped (21) 



Thorax Avithout stripes (25) 



21 Dorsum of thorax with four longitudinal lines, posterior 



margin, white poUinose; abdomen opaque black. Cuban 



species q u a d r i v i 1 1 a t u ra 



Not with four stripes (22) 



22 Dorsum of the thorax with five stripes, the outer ones spot- 



like, the intermediate ones clubbed at the ends; abdomen 

 with black fascia on each segment, produced posteriorly 

 at the middle and the ends. Sometimes the last few seg- 

 ments have only three or five spots v i 1 1 a t u m 



Thorax with one or three stripes (23) 



23 With throe stripes (24) 



" With an indication of a darker median vitta " [see 31] . . . .g r i s e u m 



24 Small species, length about 1.5mm. "Abdomen silvery, 



third and fourth segments wholly brownish, sometimes 

 with a median spot on each; legs yellowish, tarsi blackish 

 or brownish." Species from Texas tamaulipense 



Larger species 3nim. or more in length (24a) 



24a Middle tibiae brown with a yellow ring beyond the base; 

 vittae of mesouotum brownish, the median vitta dilated 

 posteriorly, wider than either of the lateral ones. New 

 Mexico virgatum 



Femora and tibiae grayish, sometimes quite pale, tips of 

 tibiae black. Laterodorsal thoracic stripes clubbed at the 

 anterior end. Third, fourth, fifth, and part of sixth and 

 seventh abdominal segments with velvet black fasciae; 

 center of (i, 7, and 8, grayish or dull brown pictipes 



25 Abdomen without distinct blacls spots (26) 



Abdomen spotted (31) 



26 Abdomen black, covered Avith long yellow pile; legs yellow, 



the tips of the femora and tibiae, and all the tarsi except 



basal tAvo thirds of the hind metatarsi, brown b r a c t e a t u m 



Abdomen nearly bare (27) 



27 Body gray or cinereous (28) 



Body brown or black (29) 



