1882.] «5l5 [Williston. 



and base of tibiae brown or brownish-black. Wings tinged with brownish, 

 the stigma darker, third longitudinal vein very slightly curved. Long. 

 Corp. 9-10 mm. Four specimens. Washington Ter. 



VIII. 



J. — Small cross-vein before the middle of the discal cell. 

 2. — Antennae short, 

 a.— Marginal cell open, 

 aa. — Face tuberculate or hyperstoma produced. 



**. — xlbdomeu contracted toward the base, more or less club- 

 shaped. 



S. — Posterior femora slender ; wings usually with brown ; face tubercu- 

 late ; hyperstoma retreating ; longer, more slender species 



Bacha {Ocyptamus). 



The differences between these two genera I cannot satisfactorily make 

 out. I have two species of Bacha from California, both of which seem 

 different from : 



*Bacha lemur O. S., West Dipt., 331. Cal., ISTew Mexico and : 



*Bach.\ angusta O. S., West Dipt., 332, California. 



SS. — Posterior femora swollen; hyperstoma produced; short, small 'spe- 

 cies. 

 T. — Hyperstoma produced anteriorly, in profile deeply concave from 

 antennse to tip; third joint of antennte nearly orbicular; the 

 fourth longitudinal vein joins the third in a right or acute angle. . 



Sphegina. 



Three species from Washington Territory and Oregon correspond pretty 

 well with S. LOBATA Lw., S. infuscata Lw. and S. rufivextets Lw., 

 but in the absence of better material in this genus, I will not venture to 

 describe them. 



TT.— Hyperstoma produced more downward, in profile very slightly con- 

 cave from antenme to tip, the fourth longitudinal vein" joins the 

 third in nearly a right or obtuse angle Ascia. 



ASCIA METALLIC A, Sp. nOV. 



(5^$. — Front and face metallic bronze black, shining, the latter white 

 pollinose. Antennae black, third joint brownish-black below, near the 

 base red. Thorax metallic-green black, finely punctui'cd. Abdomen like 

 the thorax, the third segment, in the female, with two, small or indis- 

 tinct, spots near the front ; in the male the front half except the angles red. 

 Legs with the anterior and middle femora, except the base and ends, the 

 posterior coxne, femora, except the basal fourth, tibiae, except the basal 

 third and tips, and the posterior metatarsi black, other parts light yellow. 

 Wings hyaline. Long. corp. 4-5 mm. 



Three specimens, Mt. Hood, Oregon. 



PROC. AMER. PHILOS. SOC. XX. 112. 2x. PRINTED AUGUST 8, 1882. 



