TEXAN HYMENOPTERA. 265 



clothed with cinereous pubescence, long and more dense laterally, short and 

 slightly mixed with black at apex, the fourth and fifth segments have pale pu- 

 bescence mixed with the black and the apical fringe on the fourth segment ig 

 long, sides of the segments with long white pubescence; apex deeply exca- 

 vated centrally, the apical edge notched in the middle, with the edge on either 

 side finely denticulated. Length .50 inch. 



Two specimens. (Belfrage.) 



Megachile arnica, n. sp. 



%.— Black; face and clypeus with long very dense white sericeous pubes- 

 cence, that on vertex long, thin and greenish-cinereous, that on cheeks short 

 and snow-white, longer beneath ; head smaller than usual ; antennae black, apex 

 subcompressed and slightly dilated; thorax above clothed with a long, dense 

 greenish-cinereous pubescence, longer posteriorly, and long and white on 

 pleura; tegulse with long cinereous pubescence ; wings hyaline, slightly dusky 

 at tips; legs with whitish sericeous pubescence, long oa femora beneath, each 

 anterior coxa with a short blunt spine, their femora and tibiae within more or 

 less, and the latter at tips, yellowish, their tarsi pale yellowish, flattened, not 

 much dilated, fringed posteriorly with long snow-white pubescence, that with- 

 in shorter, coarse, black and dilated at tips, first joint about as long as the 

 three following combined, which are short and decrease gradually in length, 

 claws cleft and tipped with black; intermediate tarsi slender, simple, the basal 

 joint posteriorly with along snow-white fringe of white hairs, posterior tro- 

 chanters with a tuft of long white pubescence; abdomen as broad as thorax, 

 slightly narrowed posteriorly, shining, feebly punctured, clothed with a short 

 black pubescence, interspersed with a longer cinereous pubescence, longer and 

 more dense at base, apical margin of the segments with a narrow fringe of 

 dense snow-white pubescence, much longer laterally, apex beneath with long, 

 dense white pubescence, above the segment is gradually rather obtusely 

 pointed, beneath the edge is broadly concave, the lateral angles rather promi- 

 nent. Length .40 inch. 



Two specimens. (Belfrage.) 



Megachile exilis, n. sp. 



£. — Small, black, densely and strongly punctured; head large, broader 

 than thorax, face, clypeus and cheeks beneath clothed with long, dense, snow- 

 white pubescence, on the vertex it is very sparse and on cheeks above short, 

 on middle of face and base of clypeus the pubescence is less dense and slightly 

 mixed with dusky; antennae slender, black, pointed at tip; prothorax, meta- 

 thorax and pleura beneath with long white pubescence; tegulse piceous ; wings 

 hyaline, more or less dusky at tips ; legs clothed with short white pubescence, 

 long on femora beneath, anterior tarsi pale ferruginous, three basal joints flat, 

 dilated, fringed with pale pubescence, second joint' shorter than first and 

 rather broader, the anterior margin rounded, third joint much smaller, fourth 

 slender, apical joint long, slender, claws cleft, tipped with black; four pos- 

 terior tarsi slender, simple, fringed posteriorly with long white pubescence; 

 abdomen convex, sides parallel, not narrowed posteriorly, strongly, not very 

 closely punctured, segments transversely depressed at base, clothed with a 

 very short pale subsericeous pubescence, first segment with a deep shining 

 concavity at base, apex with a marginal fringe of snow-white pubescence, 

 more dense laterally, apical margin of four following segments narrowly 



TRANS. AMER. ENT. S0C. IV. (34) NOVEMBER, 1S72. 



