11- [August 



and trochanters beneath, and the anterior femora and tibife in front. 

 are white ; the markings of the abdomen above are much the same, 

 except that the sixth segment has a band similar to that on the fifth ; 

 the apical segment is entirely fulvotis. with a divergent tooth on each 

 side at tip ; the renter is pale fulvous, the second and third segments 

 have each a whitish band, the former sinuate anteriorly, and the third 

 segment has a whitish spot on each side. Length 4f lines; expanse 

 of wings 7 J lines. 



Huh. — Rocky Mountains, Colorado Territory. (Ridings.) Coll. Ent. 

 Soc. Philad. 



7. Eucerceris canaliculatas. Say. 



F'r.Uarithu.s canaUcu!atu.i, Say. "West. Quar. Rep. ii. p. 79: American Ento- 

 mology, plate 49. 



•' Pale yellow ; vertex, disk of the thorax, and incisures of the ter- 

 gum. reddish-brown. 



■• Body pale yellow ; vertex reddish-brown ; front with t-vo loniri- 

 tndinal reddish-brown lines passing through the base of the antennae ; 

 antennae rufous, black at tip; mandibles black at tip : superior wino^ 

 with a longitudinal brownish line on the middle trom near the base to 

 the tip ; radial cellule rounded at tip, and at its inferior angle descend- 

 ing to meet the superior angle of the second cubital cellule, which is 

 triangular: tergum with a transverse groove on the middle of each 

 segment, and a marginal smaller one ; incisures reddish-brown. 



" Ob.i. — When traversing the Arkansaw region with Major Lono-'s 

 party. I obtained a single specimen of this insect, which is a male ; it 

 is so very similar in general appearance and color to Cerceris bidentata 

 nob., that but for its generic differences. I should almost have been led 

 to consider it as a mere sexual variety of that species. But it cannot be 

 placed in the genus Cerceris. as the mandibles are entirely unarmed 

 within, and the second cubital cellule is not petiolated. and the eyes 

 are not emarsinated." 



This species is unknown to me. The size of this insect is not given 

 in the description, but the figure on the plate measures 7j lines in 

 length. 



Genus CEECEEIS. Latr. 

 ffi^aff large, wider than the thorax, subquadrate ; eyes lateral, ovate, 

 entire ; ocelli in a triangle on the vertex ; antennae subelavate, in- 

 serted above the elypeus in the middle of the face, approximated, 

 mandibles stout and tridentate. acute or subacute at their apex ; clv- 

 peus trilobed. the middle lobe being often produced into various 

 shapes. Thorax ovate, the collar transverse, the metathorax obtusely 



