358 BULLETIN UNITED STATES GEOLOGICAL SUEVEY. [Tol.Y. 



finely aud closely punctured median depression. There is a triangular 

 smooth spot above the intermediate coste, and in the 9 the mesopleura 

 are slightly angulated beneath. The antenncs are similar in the two 

 sexes. — In the $ the lateral lobes of the clypeus almost touch the eyes ; 

 these lobes are bounded above by an evenly arched suture, and the me- 

 dian lobe extends no higher upon the face than the lateral lobes; the 

 median lobe is depressed, and is terminated by three teeth, the central 

 tooth minute and having a small tuft of bristles just above it; from the 

 upper portion of each of the lateral lobes arises a large and blunt conical 

 tubercle, wliich in some specimens is slightly curved downwards. The 

 labrum is slightly narrowed anteriorly, and the anterior border is deeply 

 and broadly emarginate. The mandibles are stout and armed with a 

 short, broad tooth near the apex. • The sixth ventral segment is deeply 

 cleft at the apex, so as to form two flat, parallel, black lobes, between 

 which the sting is protruded. — In the <? the lateral lobes of the clyijeus 

 are much narrower, distinctly separated from the eyes, do not extend, 

 as high as the median lobe, and are bounded above by an arched suture, 

 with the outer side of the arch much longer than the inner; the median 

 lobe has three teeth at the apex, the central tooth the longest; the 

 mandibles are more slender aud without teeth ; the labrum is a narrow, 

 curved band, concealed under the clypeus. The carinse bounding en- 

 closure on seventh segment of the abdomen terminate in projecting 

 teeth, and between them extends a process from the eighth ventral seg- 

 ment, bearing two similar teeth at its apex ; the third and fourth ven- 

 tral segments bear an apical fiinge of long, curved bristles, and the 

 apical margin of the fifth ventral segment has a row of short, evenly cut 

 bristles, which are so numerous and closely appressed as to have the 

 appearance of a rigid chitinous i^late. This fringe on the fifth ventral 

 segment is probably of the same nature as the ''waxed moustache" on 

 the clypeus of <? Cerceris. 



These specimens show considerable variation in the markings. The 

 head behind the eyes varies from dark ferruginous to yellow, the vertex 

 from dark ferruginous to honey-yellow with two pale yellow spots; in 

 many of the males there is a transverse black band between the sum- 

 mits of the ej^es, including the ocelli, and in some specimens connected 

 bj" slender black lines with the base of antennse, and also connected 

 with a short black line on the anterior orbit; in other specimens the 

 yellow of the face is continued upwards to include the ocelli, and the 

 vertical stripes at the base of antennae are short and ferruginous; the 

 mesoscutum varies from dark ferruginous with a yellow lateral border 

 to reddish-yellow, in some specimens there being- two median stripes of 

 yellow ; in some males the anterior and i)osterior borders of the mesoscu- 

 tum are black, the black of the anterior border extending upon the disk 

 in the form of three strijies; the sutures of the thorax vary from black 

 to ferruginous ; the metathorax in all the specimens is entirely or almost 

 entirely yellow; the legs vary from ferruginous to honey-yellow and to 



