No. 2326. THREE TRIBES OF WHNEUMONINAE—CUSHMAN. 15 



National Museum labelled Acrodactyla madida Haliday is correctly 

 determined, for this specimen lacks the cristulae, while Foerster's 

 genus possesses them. In this respect PGlemo'plithorus is more closely 

 allied to Colpomeria and possibly synonymous with it. Since no 

 specimen of Polemophthorus is available for study and Foerster does 

 not state the structure of the tibiae it is impossible to form a definite 

 opinion in regard to the synonymy. As regards the synonymy of 

 Oxyrrhexis Foerster and Acrodactyla Haliday the same is true, since 

 no specimen of the genotyiDe of the former genus, OxyrrJiexis carbo- 

 nator (Gravenhorst) is available. Judging, however, from the de- 

 scription of carhonator it seems improbable that the synonymy is well 

 founded, for that species is said to have the abdomen very strongly 

 punctate, whereas one of the most conspicuous characters of Acro- 

 dactyla madida, as represented in the United States National Museum, 

 is its entirely impunctate abdomen. Polemophthorus and Oxyr- 

 rhexis will therefore be eliminated from further consideration because 

 of the lack of specimens and because of the uncertainty of their 

 affinities. 



In the present paper Acrodactyla and Colpomeria are treated as 

 genera, while Zatypota is considered as a subgenus of Polysphincta. 



In general appearance and form, largely influenced by the abdom- 

 inal structure, the genera comprising this tribe bear a very strong 

 superficial resemblance to the typical Ichneumonini. But the very 

 peculiar host-relations and the more minute structure, especially in 

 the female, render them very distinct. These featmres are very 

 reminiscent of certain genera of the Tryphoniae, such as Monohlastus 

 Hartig and Polyblastus Hartig, and of the Paniscini. 



Description. — Head strongly transverse, temples flat or slightly 

 rounded, sloping sharply to the strong and complete occipital carina; 

 face convergent below and at least as long as wide at clypeus, the 

 latter convex or slightly flattened, usually rounded at apex, and 

 frequently with a reflexed margin, rarely very weakly, broadly 

 emarginate, never medially impressed or inflexed; mandibles narrow 

 at apex, bidentate, the upper tooth the longer; eyes and ocelli large; 

 antennae long, filiform. Thorax subovate, usually more or less dis- 

 tinctly compressed; notauli strongly impressed throughout, converg- 

 ing posteriorly, the prescutum very prominent, rarely broad and 

 shallow, but in this case the prescutum is nevertheless very long 

 and most of the other characters are especially well-marked; scu- 

 tellum elevated and more or less distinctly compressed from the 

 sides; propodeum rarely without carinae, frequently with two well- 

 defined median areas, the petiolar and the confluent areola and basal 

 area; wings broad, stigma rather small, usually narrow lanceolate, 

 areolet rarely complete or even defined; third discoidal cell usually 

 strongly narrowed basally, nerveUus broken at, below, or not far 



