84 KANSAS UNIVERSITY SCIENCE BULLETIN. 



yellow, the third black, rather pointed, arista inserted near 

 the base ; palpi rather pointed, yellow ; occiput with gray dust, 

 the orbital bristles small, at the sides and below whitish. 

 Thorax dark green above, with thin dust and rather large bris- 

 tles ; pleurae black, with dense, almost white, dust ; tegular 

 cilia dark, in some lights almost russet, in others blackish ; 

 hal teres yellow ; abdomen not elongated, scarcely equaling the 

 head and thorax in length, not compressed, dull green in color, 

 with row of longer hairs at the margin of each segment ; hypo- 

 pygium black, thick, rounded, protruding behind and below on 

 the ventral side, making up nearly half the length of the abdo- 

 men, with some partially concealed slender yellow parts at the 

 front end. Middle coxte infuscated on the outer side, the other 

 coxae and all the feet yellow ; the tarsi scarcely infuscated ; 

 fore tarsi as long as the tibia, the last three joints of equal 

 length, the fifth black, the inner claw stout, black, curved back 

 upon the joint to form a clasping organ, very much as in S. 

 faJco; the outer claw normal. On the front side of the hind 

 femur below is a row of black bristles, longer toward the tip ; 

 wings grayish, the last section of the fourth vein almost per- 

 fectly straight, the third converging toward it at tip. 



Female : Like the male, but the face not narrowed below ; 

 the fore tarsi normal ; no bristles on hind tibiee. 



Length, 2.2 to 2.4 mm. ; of wing, 2 mm. Numerous speci- 

 mens, both sexes. This species, with falco and similis and the 

 Mexican coxalis, forms a group of close relationship, yet suf- 

 ficiently distinct from each other. 



Sympyonus falco. 



Aldrich, Trans. Lond. Entom. Soc, 1896, 336. 



Two females. The black antennae and plain fore tibiae suf- 

 ficiently distinguish the females from those of the related 

 species. 



Sympyonus similis. 



Aldrich, Trans. Lond. Entom. Soc, 1896, 336. 



Two males, two females. The row of bristles on the fore 

 tibia occurs also in the female, making an easy distinguishing 

 mark. 



