260 Mr. T. D. A. Cockerell — Vescriptio^is and 



sharp basal tooth. Head large, round ; cheeks flattened, not 

 spined ; punctures of head and thorax dense and coarse, on a 

 dullish surface, but clypeus (convex in middle) and middle o£ 

 supraclypeal area shining, with well-separated strong punc- 

 tures ; hair of head and thorax greyish white, the vertex also 

 with dark fuscous hair, very short and easily overlooked ; 

 antennse dark ; mandibles short and thick, 4-dentate, fringed 

 beneath with pale golden hairs ; first joint of labial palpi about 

 ^ or f length of second ; tegulaj black. Wings strongly 

 and broadly infuscated on apical margin ; nervures black. 

 Abdomen strongly but not densely punctured, with narrow 

 white hair- bands, more or less failing in the middle; sixth 

 dorsal segment rapidly descending, strongly concave in 

 piotile, its basal half with sparse, erect, pale hair, its apical 

 with pale tomentum. Legs black, tlie tarsi (especially the 

 middle and hind ones) broad and thick ; hind basitarsus not 

 quite so long as the other joints together, if claw is included. 

 Third joint of maxillary palpi with very tine short pubescence 

 and shorter than 1 + 2. 



Belongs to the subgenus Sat/apis, and is related to M. sayi, 

 Cresson, but easily distinguished by the shining sparsely- 

 punctured clypeus, the character of the clypeal margin, and 

 the wholly white ventral scopa. 



Uab. Boulder, Colorado, at flowers of Helianthiis Unticu- 

 laris, Aug. 29, 1906 {S. A. Rohwer). 



Megachile terrestris, sp. n. 



$ . — Length about 10^ mm. 



Black, moderately robust, in build something like M. monti- 

 vaga or M. melanopyga, the abdomen strongly convex in 

 profile ; ventral scopa tntirely rather 2^<^is orange, as are the 

 narrow but very distinct abdominal bands ; cli/peus undulate, 

 loith three low broad dentiform angles, one being median ; 

 claws with a strong basal tooth. Head and thorax densely 

 punctured, with the copious long pubescence very pale 

 yellowish, becoming strongly fulvous on clypeus, lower part 

 of cheeks, and vertex, and a little so in middle of mesothorax ; 

 head ordinary ; clypeus closely punctured but shining ; 

 mandibles with only three distinct teeth, the innermost 

 rounded ; first joint of labial palpi a little shorter than 

 second ; last joint of maxillary palpi with the pubescence 

 very short, indistinct ; antennge dark ; mesothorax dull ; 

 tegulse piceous. W ings strongly infuscated, yellower basally ; 

 nervures ferruginous, the outer ones piceous. Tarsi f err u- 

 (jinous, more or less infuscated, and clothed with orange- 



