142 Proceedings of the Biological Society of Washiiigton. 



teriorly nearly bare, laterad and basad of this with moderately long pale 

 hairs; hypopygium with rather dense pale hairs. Hind femur as thick as 

 first tergite; hind tibia with a beaklike apical process as in last species; hind 

 trochanters with some minute black setulae below. Other cross-vein about 

 twice as long as its distance from bend of fourth vein. 



Female. — Differs from the male in lacking the yellow mark on second 

 tergite, and in having two poorly defined rufous marks at base of third. 



The first tergite is broader than in male, and not so long as the next tw-o 

 combined, the fourth is slightly flared at apex owing to the presence of a 

 shallow transverse preapical depression, and is conspicuously hairy as is 

 also the fifth sternite. The hind trochanters in allotype are as in type, but 

 in the paratype there are no black setulae present. The hind tibiae lack 

 the apical beaklike process in both specimens. 



Length, 8-9 mm. 



Type. — Bairs Ranch, Redwood Creek, Humboldt Co., Calif., June 11, 

 1908 (H. S. Barber). Allotype, female, Walnut Creek, Contra Costa Co., 

 Calif., May 13. Paratypes, one female, Los Angeles Co., Calif, (coll. 

 Coquillett), one male, Dewatto, Wash., June 7, 1906 (J. M. Aldrich), one 

 male, Moscow Mt., Ida., June 4, 1910 (J. M. Aldrich), one male, Waha, 

 Ida., June 18, 1909 (J. M. Aldrich). 



Sphegina armatipes, var. rufa, var. n. 



Male. — Rufous, frons fuscous, abdomen suffused with castaneous, bases 

 and apices of hind tibiae and all of hind tarsi fuscous. 



Structurally similar to the type form, differing as follows: Arista more 

 slender and less densely pubescent, hind femora not so thick, the process at 

 apex of hind tibia rounded at tip and compressed from each side, and the 

 hind trochanters without black setulae. 



Length, 8 mm. 



T?/pe.— Fieldbrook, Humboldt Co., Calif., May 29, 1903 (H. S. Barber). 



Sphegina monticola, sp. n. 



Female. — Fulvous, shining. Frons and upper half of face fuscous. 

 Apices of tergites 1 to 3 dark brown. Apical half of hind femur black, basal 

 segment of hind tarsus and apical two segments of all tarsi brown. 



Frons about one fourth of the head width, very short haired. The curved 

 linear thoracic depression complete. First tergite slender basally, not as 

 long as next two together, third flared at apex, fourth with a deep notch in 

 center of posterior margin. Hind legs as in campanidata Robertson. 



Length, 7 mm. 



Type.— Mt. Washington, N. H. 



Sphegma occidentalis, sp. n. 



Male and Female. — Head black, antennae brown, face yellowish in middle 

 below. Thorax black, humeri and postalar callosity reddish. Abdomen 

 in male black, with the base of second tergite broadly yellow, in female 

 rufous. Legs yellow, hind femora black except bases, basal segment of 

 hind tarsi brown, the apical two segments of all tarsi hardly darkened. 



