216 BULLETIN 31, UNITED STATES NATIONAL MUSEUM. 



so; jn'oduced downwards. Front in female black on upper i)art, with 

 short blackish ])ile, below like the lace; frontal trianjile in male yellow, 

 eyes rather more coutiffuous thau in analis,the frontal process rather less 

 projectiuji:. Antennae yellowish brown, or blackish brown, the second 

 joint sometimes yellow with lilack above, the third joint always of a 

 lighter color below. Thorax shining" greenish black ; dorsum with 

 blackish pile across the middle, in front and on the scutellum, yellow; 

 humeri yellow with a small continent spot below, meso-pleura^ yellow- 

 ish gray iiollinose and pilose. Scutellum black, the edge sometimes 

 narrowly luteous. Abdomen black ; second segment opaque, with 

 two large yellow spots, narrowly separated, rounded on their inner 

 ends and narrowed toward the margin ; third segment with a yellow 

 cross-band on the anterior part, doubly convex behind (the greatest 

 convexity being toward the middle), with a sharp, median angular in- 

 cision behind, and attenuated nearly to a point on the sides of the ab- 

 domen ; fourth segment similar in female, in male wholly black, or 

 with a triangular spot in front and reddish behind ; hypopygium red- 

 dish or yellow ; fifth segment in female yellow in front ; black at tip. 

 Front COX8B white pollinose in front; all the femora black, excejjtthe 

 tip; front and middle tibise and metatarsi yellow or reddish yellow; 

 hind tibiae yellow at the base and tip, a broad ring in their middle, and 

 the hind tarsi, blackish brown. Wings yellowish hyaline. 

 Four specimens. 



SOMULA.* 



Criorhiua (Somula) decora. (Plate X, figs. 3, 3a, 36.) 



Somula decora Macquart, Dipt. Exot., 2<^ Suppl., 57, 1; tab. ii, fig. 11 ; Osten 

 Sackea, Cat. Dipt., 138. 



Habitat. — Eastern and Middle States ! 



5,9. Lengtii, 14tolG'"". Antennal process conical, very prominent. 

 AntenucB brow^uish-black. Face below the antenna! process very slight- 

 ly concave, descending perpendicularly considerably below the eyes ; 

 gently convex, light yellow, shining, except near the eyes a small s])ot 

 is whitish dusted. Cheeks shining black. Front in the female black 

 on the upper ])art ; below in both sexes the upper part of the antennal 

 process is black, the yellow of the face extends up on each side, cutting 

 off the black of the upi)er jtortion from that below ; pile of the front and 

 the np})er part of the occiput black, on the narrow orbits below light 

 yellow. Thorax deeply shining metallic greenish-black, with short, 

 sparse, and obscurely yellowish and black pile ; humeri opaque yellow, 

 with yellow pile, meso-pleunie with a large oval yellow si)ot and abun- 

 dant yellow pile. Scutellum like the thorax. Tegulae yellow. Abdo- 

 men black, with three or four pairs of conspicuous, oblique, large, oval^ 

 bright yellow, opaque spots ; the first pair on the second segment^ 



* For tlie definition of this genus see page 209. 



