160 U. S. NATIONAL MUSEUM BULLETIN 216 parts 



sent; tegula, subtegular ridge, spot on scutellum and postscutellum, 

 and sometimes stripe below and spot above sternaulus, white; rarely 

 the front, lower, and upper margins of pronotum, and a spot in center 

 of mesoscntum, white, and rarely a subapical tranverse band on propo- 

 deum, white; front and middle coxae and trochanters entirely white or 

 sometimes partly blackish; front and middle legs beyond trochanters 

 fulvous, the front tarsus brown apically and the middle tarsus brown 

 but pale at the joints; hind coxa and first trochanter black, the coxa 

 often white at apex; hind second trochanter more or less fulvous, fus- 

 cous, or white; hind femur ferruginous, the apical 0.12 ± usually in- 

 fuscate, or sometimes most or all of the femur infuscate, or rarely 

 black; hind tibia brownish, its apex blackish, sometimes its base 

 brownish fulvous, and sometimes with a subbasal narrow, indistinct, 

 whitish or stramineous band; first and last segments of hind tarsus 

 black, the three middle segments and sometimes the apex of first seg- 

 ment, white; first tergite black, its apex sometimes ferruginous; ter- 

 gites 2-4 entu'ely ferruginous or sometimes more or less infuscate; fifth 

 and following tergites entirely black or sometimes the fifth tergite 

 ferruginous basally. 



Female: Black. Sometimes clypeus and facial orbits white; man- 

 dible rarely partly white; palpi fuscous or sometimes white; fla- 

 gellum with a narrow to broad white band that is usually incomplete 

 below, or sometimes the band lacking; tegula fuscous or white, the 

 rest of thorax black except rarely for whitish marks on collar and 

 upper edge of pronotum; front and middle coxae fuscous to fulvous 

 basally, whitish apically; front and middle trochanters largely or en- 

 tu"ely whitish; front and middle legs beyond trochanters ferruginous, 

 the fifth segments of their tarsi brown ; hind coxa and fu'st troclianter 

 fuscous; hind second trochanter and hind femur ferruginous, the apex 

 of the femur often weakly infuscate; hind tibia ferruginous with its 

 apex a little infuscate to dark reddish brown with its base paler, rarely 

 with a subbasal, narrow, indistinct, paler band; hind tarsus blackish 

 brown, its second segment usually and third segment, fourth segment, 

 and apex of fh-st segment sometimes, whitish; first three tergites 

 ferruginous, the basal half of first tergite more or less infuscate; fourth 

 tergite ferruginous or sometimes black; fifth and following tergites 

 black. 



The species is quite variable and may prove to be either a com- 

 posite species or only subspecificially distinct from /. 7'homhoidalis , 

 I. politus, and /. lautus. Specimens from the western half of its 

 range tend to have the mesoscutum more polished, mesoscutal punc- 

 tures stronger, and often the clypeus wider and female flagellum shorter 

 than is typical for the species. In this way they approach 7. lautus. 

 Some females from Alaska, Yukon, British Columbia, and Colorado 



