322 BULLETIN 45, UNITED STATES NATIONAL MUSEUM. 



length, the third, slightly the thickest; in the $ the secouil funiclar joint 

 is stout and slightly curved, the club joiuts being not more than 1 J times 

 as long as thick; the three middle joints outwardly subserrate, the last 

 conically pointed, much longer than the preceding; the legs are black, 

 the tip of anterior tibia' and tarsi fuscous, while the wings are slightly 

 smoky. 



Habitat. — San Francisco :ind Alameda, Cal. 



Types in National Museum. 



Described from many specimens, reared by A. Koebele, January 10 

 and 23, 1883, and July 10 and December 17 and 10, 1885, from a Cecido- 

 myiid gall found on BHccharia pUnlarh. 



PLATYGASTER Latreille. 



Geu. Cms. et Ins., iv, p. 31 (1809); Eorster Hym. Stud., ii, p. 108 (1856). 



(Type P. ruficornis Latr.) 



Head transverse, rarely subquadrate, the vertex somewhat narrowed, 

 convex, the lateral ocelli usually far away from the eye margin but 

 still nearer to it than to the front ocellus. 



Antenna'. 10-jointed, the scape subclavate, the flagellum ending in a 

 6-joiuted, filiform club, the second joint in the male a little swollen and 

 curved. 



Thorax ovate, usually more elongated than in Polycpiotus, the collar 

 usually distinct, the mesonotal furrows distinct, the scutellum convex, 

 unarmed, the metathorax short, carinated. 



Wings veinless, pubescent. 



Abdomen oblong-oval or ovate, the petiole usually distinct, at least 

 as long as wide, or a little longer, striated, the second segment very 

 long, striate at base. 



Legs long, clavate; the tibiic slender, the tarsi very long, the hind 

 tarsi being much longer than their tibia'. 



The genera Fl<(fyg<ister and Isoeybus are exceedingly closely allied, 

 but the head in Isocyhii.s is more (luadrate and the lateral ocelli are 

 nearer to the front ocellus than to the luargin of the eye. 



I am not fully satisfied that they should be kept separate, although, 

 so far, the position of the lateral ocelli seems sufficient to separate them. 



The head in Platyyaster Herriclii Packard and the position of the 

 ocelli is, hoA\"ever, wvy similar to Isoeybus. 



TABLE OF SPECIES. 



I'KMALES. 



Cox;l' Ithuk. 



L(>g8 yellow or yolilcn yellow, auteuiiie yellow, the club fuscous. 



Vertex rugose, with laised liues in the uiiddle; face closely ]imi(tiilati', with 



Bouie transverse lines on lower i)art. 



Pedicel very long; lirst I'uniclar joint a little longer than wide, the second very 



long, twice as long as the (irst ; clul) 6-iointed, the joints, except the 



last, transverse .....,, P, CARYJE Ashiu. 



