154 AMERICAN HYMENOPTERA. 



Legs. — The pile all dark. Outer faces of hind tibiae convex and 

 sparsely hairy, their fore fringes moderate and their hind fringes long, 

 forming distinct, though weak, corbiculse. Hind metatarsi fully three 

 and one-half times as long as their greatest width, their outer faces 

 distinctly concaved and their hind fringes very long. 



DiiHenstons.—L,ength: queen, 19 mm. to 21 mm.; worker, about 

 13 mm. ; male, 14 mm. to 15 mm. Spread of wings : queen, 43 mm. 

 to 46 mm. ; worker, 34 mm. ; male, nearly 35 mm. 



The queen is here redescribed from two specimens and 

 the worker from one. 



Habitat. — We have certainly valid records for this species 

 from Colombia, Venezuela and northern Argentina (Tucu- 

 man and Salta) only. There are specimens before me from 

 Colombia and Venezuela. Cameron records it from Ecuador 

 (Pichincha), at an altitude of 11,500 feet. It is almost cer- 

 tainly present in Peru, Bolivia and northern Chili. The 

 species probably has a considerably wider range than is in- 

 dicated by these records. 



Variation. — Friese has described the following forms as 

 varieties of this species : 



"1. Var. S. Segments one and two yellow-, three black-, four red-, 

 five and six white-haired. Bolivia. Var. cinctus.'' Friese has sent 

 me an identified specimen of this form, and he is apparently correct 

 in regarding it as a variety of robustus. The fourth dorsal segment, 

 however, is not red, but yellow, in the specimen sent me. This speci- 

 men came from Bolivia. 



" 2. Var. c? 9 S . Segments 1-3 black-, 4-6 white-haired. 9 usu- 

 ally with yellow tufts of hair on segment three. Banos (Ecuador). 

 Var. hortulatis .'' ^ Friese has sent me a worker and male of this form, 

 and I agree with him in considering it a variant of robustus. 



"3. Var. cf. Thorax entirely black ; segments one and two yellow-, 

 three black-, four to six white-haired. Bolivia. Ya.r. nigrothoracicus.'' 

 This form is unknown to me, as are also the two following : 



"4. Var. &^ . Thorax yellow-haired, with dark cross-band; seg- 

 ments one and two yellow-, three black-, four to six red-haired, six 

 often with single whitish hairs. Argentina (Tucuman). Var. rufo- 

 caudatus.^' ' 



"5. Var. sieinbachi. Yellow are: broad bands over pronotum and 

 scutellura, segments one and two. Black: band over mesonotum, seg- 

 ments three and four. White : end of segment four and five and six 

 entirely. (Colored exactly like Bombus asiaticus Mor.). 9. Salta, 

 Argentina, month of March (Steinbach collector)." 



