68 PROC. ENT. soc. WASH., VOL. 22, NO. 4, APRIL, 1920 



usually more transverse. These are the characters assigned to 

 Platygaster by Foerster. No specimens of Platygaster ruficornis 

 Latreille, type of the genus Platygaster, have been seen by the 

 writer but it seems certain that Ashmead 's species of Polygnotus 

 are typical Platygaster. Certainly they are if Foerster's inter- 

 pretation of Latreille's genus is correct. 



The genus Platygaster as limited by Foerster is, in the opinion 

 of the writer, too narrow and excludes many forms which cannot 

 properly be placed in any other genus. All of the characters 

 given by Foerster for separation of Platygaster and Polygnotus are 

 purely relative. Study of a large amount of material in the 

 National collection shows that there is such a perfect intergrada- 

 tion of all these characters that no line can be drawn which will 

 satisfactorily separate the two genera. Typical forms of the two 

 groups are not difficult to recognize, but in the American fauna 

 there are a large number of intermediate forms, which may as 

 well be placed in one group as the other. The writer is, therefore, 

 of the opinion that the two genera should be synonymized. 



The genus Coelopelta Ashmead, having as type the West Indian 

 species mirabilis Ashmead, is founded upon a single imperfect 

 specimen in which the scutellum is caved in from above, giving it 

 a cupuliform appearance. It is true Platygaster belonging to the 

 group in which the head is thin antero-posteriorly and the sculp- 

 ture indistinct. 



The writer would also place in Platygaster those species having 

 the scutellum unarmed which were included by Ashmead in the 

 genus Polymecus. Except in the more or less elongate abdomen 

 these species do not differ from typical Platygasters, and since 

 there are all degrees of elongation of the abdomen, the character 

 is unreliable and impracticable for generic separation. 



Certain other species described by Ashmead in the genera 

 Synopeas, Hypocampsis, and Anopedias respectively, are in the 

 writer's opinion, wrongly placed and belong in Platygaster. 



Besides the species of Polygnotus and Coelopelta described by 

 Ashmead, the following species should be transferred to Platy- 

 gaster : 



Polymecus canadensis Ashmead. 

 Polymecus americanus Ashmead. 

 Polymecus pallipes Ashmead. 

 Polymecus nigrifemur Ashmead. 

 Polymecus vancouverensis Ashmead 

 Polymecus lupinicola Ashmead. 

 Polymecus picipes Ashmead. 



Polymecus melliscapus Ashmead. 

 Polymecus compressiventris Ashmead. 

 Polymecus alnicola Ashmead. 

 Synopeas antennariae Ashmead. 

 Synopeas melanoceras Ashmead. 

 Anopedias pentatomus Ashmead. 

 Hypocampsis pluto Ashmead. 



