Fossorial ITymenoptcra of North America. 107 



in its antennae having the scape entirely yellow, instead of being 

 striped with black, and in 0. montanus tbe slope of the propodeum is 

 very great, while in tbe present species it is nearly horizontal, and in 

 size much smaller, and the nieta-seutellum is entirely black. 



A specimen from Brunswick, Maine, has the inner side of the basal 

 three-fourths of the scape black, a yellow stripe on the prothorax in- 

 terrupted more on the mesial line than in the Illinois specimens; the 

 enclosure of the propodeum is much more coarsely striate, there being 

 one-half as many rugae, thus showing that the amount of striation of 

 this triangular area, though generally very useful in distinguishing the 

 species, cannot always be depended upon. Also, the fore femora are 

 entirely black, and the middle femora are provided with a yellow dot 

 at the tip, instead of being ringed with yellow, while the abdominal fas- 

 ciae are a little broader, and the terminal pair are ovate, instead of round 

 as in the specimens from Illinois. 



Found flying about Spiraea alba in August. 



Crabro corrugatus. n. sp. 



9 . Head cubical, finely punctured, a little more than one-third 

 as long as broad; vertex convex, not channelled towards the antennal 

 groove, ocelli arranged in a low triangle, anterior one in a well marked 

 circular depression. Antennal groove lined broadly on each side with 

 a very fine silvery pubescence, finer than that on the outer side of the 

 orbits ; elypeal region silvery, clypeus nearly two-thirds as long as 

 broad, well carinated ; mandibles tridentate, teeth acute as usual, 

 greenish yellow in the middle. Palpi fuscous, joints of moderate 

 width, the terminal one long, slender obconic, one-third longer than 

 the penultimate. Antennas clavate, towards tips closely jointed, su- 

 tures slight, scape clavate increasing in width gradually towards the tip, 

 pale yellow with a broad, ovate black patch above, flagellum black. 



Prothorax not so broad as usual, not angulated on the sides, mesial 

 notch well defined, the length, antero-posteriorly of the scutum is 

 greater than usual, each half yellow, slightly carinated on the front 

 and hinder edge, not however, as usual, terminating in well marked 

 denticles, surface concave slightly. Mesoscutellum unusually smooth, 

 being very finely puncto-striated, the anterior raphe and submesial ridge 

 plainly marked; scutelluui puncto-striated; meta-scutellum smooth, 

 yellow : propodeum with a broad mesial lino, dilated at base and 

 on the posteriorly vertical face, with four transverse ridges ; on each 

 side a few large, remote curved, sinuate, irregular ridges, with abbre- 

 viated, transverse, smaller rugae. Each side of the enclosure is sub- 



