NORTH AMERICAN DIGGER WASPS— FERNALD. 321 



the fore femora are slightly grooved beneath, near the tips; tibiae 

 shorter than the femora except the hindei- pair which equal theii' femora 

 in length; sericeous and with numerous rather short, stout spines; 

 tarsi })^lack with a ver}- slight ferruginous tinge; sericeous; fore meta- 

 tarsus with six or seven (usuall}^ six) comb teeth, long and stout; claws 

 ferruginous, blackish at base, with two blunt teeth on the iimer edge 

 near the base; hind tibia and base of hind metatarsus strongly brown 

 sericeous behind; hind tibial spine with separated, short, blunt teeth 

 on its outer half; inner contour of hind tibia straight on the outer half 

 but with an abrupt inward crook near the l)ase, seen when the tibia is 

 viewed from behind. 



M((/e. — Ditfers from the female as follows: Mandilde with two teeth: 

 edge of clypeus with a less developed sinus; ej'es converging down- 

 ward; the four indentations near the ocelli v^ery faint, particularly the 

 upper pair; median groove of mesonotuni with more pronounced edges; 

 petiole longer than in the female, usually as long as the posterior coxae, 

 slightly shorter than the first and second tilament segments together, 

 but longer than the lirst and half the second; second and third ventral 

 abdominal plates not emarginate behind; fourth and iifth brown, silky 

 sericeous, the former somewhat emarginate behind, the latter with a 

 slight, broad emargination; sixth and seventh narrow from side to 

 side, the sixth l)roadly emarginate, the seventh almost broadly notched 

 rather than excavate; terminal ventral plate very narrow, (juadrangu- 

 lar, its hinder margin with a central notch on each side of which it is 

 arcuate; the last two ventral plates nearly enveloped ])y the last dorsal 

 plate, the hinder margin of which is rounded conical; hind tibije viewed 

 from behind, with an abrupt inward crook near the base; outer borders 

 of the wings lighter than the remainder. 



LeiKjtli. — Females, 19-!^8 nun.; males, 15-22 mm. 



Some variations from the characters described above are met with 

 in certain cases. There seems to be a tendenc}' for portions of the 

 first and second dorsal abdominal plates to show a faint tinge of brown 

 or ferruginous; seven teeth in the metatarsal comb are not uncom- 

 mon, and in one specimen seen there were seven on one side and six 

 on the other; wdiile pubescence on the face is generally absent, traces 

 of it may often be noted; rarely the petiole is shorter than the hind 

 coxa3. 



Cresson's description is defective in that not all the males, even in 

 the lot before him when his desciiption was prepared, have a silvery 

 clypeus, and the thorax is not really smooth as he stated, though it does 

 have that appearance when not closely scrutinized. 



Dlsti'ihutlon. — I have seen specimens of this species from the 

 Yakima River and the Grand Coulee, Washington; Crow Heart Butte, 

 Wyoming: Missoula, and Flathead County, Montana; Ormsby County, 

 and Reno, Nevada; from Dakota, Colorado, Nebraska, and Kansas; and 



