1863.] 
69 
Description of a new species of MASABIS, from the Rocky Mountains. 
BY E. T. CRESSON. 
Masaris vespoides n. sp. 
Male. (Plate 4, fig. 1.) Length lines; expanse of wings 15 
lines. Head coarsely punctured, sparsely clothed with pale hairs; face 
above the antennae flat; eyes large, with a deep, narrow sinus above 
the insertion of the antennae; ocelli placed in an equi-lateral triangle 
on the vertex; clypeus convex, subquadrate, deeply emarginate at the 
apex with the angles rounded; labrum rounded at tip, hairy; mandi¬ 
bles somewhat obtuse, with two small indentations on the inner edge 
near the apex; antennas smooth, a little longer than the head and tho¬ 
rax together, first joint short and thick, second very small,- third to 
sixth joints somewhat flat and about equal in length, each joint being 
about twice as long as the first and second together, seventh joint two- 
thirds as long as the sixth, rather flat and broader than the preceding 
joints, the five apical joints formed into a broad oval knob slightly 
convex above and concave beneath, these five joints are apparently sol¬ 
dered together with the sutures very indistinct above but more distinct 
beneath. Prothorax prominent, closely punctured, hairy. Mesotho- 
rax oval and convex in front, sparsely hairy, closely and confluently 
punctured; somewhat flat before the scutellum where it is sparsely 
punctured, shining and with the posterior margin truncate. Scutel¬ 
lum semicircular, convex, sparsely punctured and shining. Wing-scale 
elongate and reniform. Metathorax somewhat flat, densely punctured, 
hairy, the posterior angles terminating on each side with an acute spine. 
Legs hairy, rather short, the posterior pair longest; anterior femora 
clavate, broadest near the base, and curved inward; tibiae shorter than 
the femora, somewhat excavated on the inner edge towards the base; 
anterior tarsi ciliated beneath, and all, except the posterior pair, have the 
first joint as long as the remaining joints taken together; intermedi¬ 
ate femora short, thick, not clavate, sinuate beneath; inner edge of the 
tibiae deeply excavated from the middle to the base and sulcate, broad¬ 
ly dilated in the middle and somewhat suddenly constricted towards 
the apex; posterior femora somewhat clavate; tibiae longer than the 
