CHARLES W. METZ. 143 



short and narrow. Between the typical females of this and 

 P. zi'ootoni there is apparently more or less intergradation, 

 making absolute distinction impossible in some cases ; in 

 general, however, separation can be made as stated. 



PROSOPIS CALVUS n. sp. 



Male. — Small species; nearest to coloradeiisis, but differs in the nar- 

 rower face, short, narrow, lateral face marks, and entirely different 

 genitalia. 



Length about 5 mm. ; slender; posterior face of propodeum small, 

 not cut oflf squarely, but rounded above ; scape short, stout, similar to 

 that of coloradensis ; fiagellum normal, light beneath ; clypeus long, 

 narrow at base, about two-thirds the width of the lateral areas at same 

 level; surpraclypeal area below antennal sockets longer than broad. 



Sculpture. — Head, thorax, and abdomen heavily punctured with large 

 punctures, becoming faint on cheeks. Mesoscutum heavily punctured 

 with medium sized punctures, considerably smaller than on front, 

 separated by less than the diameter of one puncture ; scutellum with 

 much larger, more sparse punctures ; metanotum over half as long as 

 scutellum, rugulose. Enclosure of propodeum broad above ; neck 

 narrow ; entire bowl shallowly pitted ; small areas laterad of bowl also 

 pitted ; lateral areas of posterior face punctured ; sides rugulose. 

 Mesopleura more sparsely punctured than mesoscutum, but punctures 

 of same size ; metapleura striate. First two segments of abdomen 

 heavily punctured, with medium sized, round punctures, separated 

 by about the diameter of one puncture ; remaining segments very 

 sparsely punctured. 



Yellow Markings. — Face marks extending very little above antennal 

 sockets, (fig. 110); supraclypeal mark not extending between antennal 

 sockets; lateral marks broad, short, filling lateral areas, but ending 

 almost abruptly at upper level of sockets. Collar with a small yellow 

 spot on each side ; tubercles with yellow spots ; other thoracic marks 

 lacking. Legs with anterior tibiae in front, basal third of middle and 

 hind tibiae, and basitarsi yellow ; other tarsi brown. 



Genitalia. — Armature short, stout ; stipes heavy, with large superior 

 lobe, and stout, rounded, heavily haired apical portion ; sagitts ex- 

 tending beyond stipites ; volsella very large, lateral lobes almost round, 

 inner lobes very small, (fig. 20). Seventh ventral plate entirely nude; 

 wings largely membranous, long, narrow ; each with a large trans- 

 parent flap on outer side ; chitinous portion of proximal arms unite 

 before they reach the extension of the wings, in a broad curve, instead 

 of close to the wings as in other species, (fig. 59). Eighth ventral 

 plate short, stout, hairless; distal pedicel short, stout, ending in two 

 long, narrow divergent lobes, without pubescence, (fig. 63). 



Female. — Unknown. 



TRANS. AM. KNT. SOC. , XXXVII. 



