No. 2317. FIVE TRIBES OF ICHNEUMONINAE—ROHWER. 423 



propodeum with two raised, median, longitudinal ridges; the propo- 

 deal spiracle about two and one-half times as long as wide and about 

 three times its length from the base of the propodeum; spiracles of the 

 first tergite close to the base, the distance between them greater than 

 the distance from one end of them to the anterior margin of the 

 segment; first sternite fused with the tergite basally; second sternite of 

 the female with the median tubecles near the base; second tergite 

 with lunulae; tergites three to six not, or but slightly, emarginate pos- 

 teriorly; abdomen of the male nearly parallel-sided and about three 

 times as long as the head and thorax; ovipositor usually somewhat 

 longer than body. 



All the species which have been reared are parasitic on horn tail lar- 

 vae of the genus Xipliydria. 



There are only two species which occur in the Nearctic fauna and 

 these are easily distinguished by color characters. One of our species 

 is very close to a common European species and the European species 

 is included in the following key for that reason. The notes on ths 

 European species are based on specimens in the United States National 

 Museum which were determined by Konow. 



TABLE TO THE SPECIES. 



1. Posterior orbits broadly yellow; mesepisternum and sternum and sides of the 



propodeum reddish-yellow, tergites with lateral yellow eipota. .humida (Sslj). 

 Posterior orbits black; mesothorax and propodeum black; tergites black 2. 



2. Apices of hind femora and tibiae black; North America nitida (Cresson). 



Hind femora and tibiae concolorous; Europe curvipes (Gravenhorst). 



RHYSSELLA HUMIDA (Say). 

 Pimpla humida Say, Bost. Journ. Nat. Hist., vol. 1, 1836, p. 224. 



The type of humida is lost and none of the specimens studied by 

 Walsh seem to be in existence. The following discussion is based on 

 specimens listed below. The female from Fort Lee, Xew Jersey, is 

 chosen as a neoty]ie. 



Distribution. — Indiana (Say, and a specimen determined by 

 Merrill) ; Illinois (Walsh) ; Connecticut (Patton) ; Fort Lee, New Jersey 

 (Zabriskie); Harrisburg, Pennsylvania (Champlain); Lyme, Con- 

 necticut (Champlain). 



Host. — Patton records this as being parasitic on the larva of 

 XipJiydria attenuata Norton and Champlain has collected it as par- 

 asitic on Xipliydria abdominalis Say and on Xipliydria erythrogastra 

 Ashmead. 



RHYSSELLA NITIDA (Cresson). 



Rhyssa nitida Cresson, Proc. Ent. Soc. Phila., vol. 3, 1864, p. 319. Male. 

 Rhyssa canadensis Cresson, Can. Ent., vol. 1, 1868, p. 35. Female. 

 Epirhyssa clavata Provancher, Addit. fauna. Can. Hjtu., 1886, p. 115. 



The types of nitida Cresson and canadensis Cresson are both in the 

 Academy of Natural Sciences, Philadelphia. The type of clavata is in 



