140 PIMPLINE ICHNEUMONIDAE 



appear first. W. H. Harrington" has given a series of obser- 

 vations made in June, 1887, in which he showed that the males 

 having issued first, awaited the females, and were able to locate 

 the spot at which a given female would emerge, some time before 

 she made her appearance. In one instance which he records, 

 a particular spot was crowded with males for two days before 

 the female emerged, and even then, she was assisted by the 

 removal of the bark by the observer. The males, in waiting, 

 make every effort to reach the female, inserting the tips of their 

 abdomen into crevices in the bark. On emerging the female 

 is instantly seized, the legs of the male clasping the yet unused 

 wings and abdomen, thus preventing her from flying. 



Genus RHYSSA Gravenhorst 



Rhyssa Gravenhorst, Ichneum. Europ., iii, 1829, p. 260. 



Epirhyssa Cresson, Proc. Ent. Soc. Phila., iv, 1865, p. 39. 



Pararhyssa Walsh, Trans. Acad. Sci. St. Louis, v, 1873, p. 109. 



Rhyssa Riley, Ins. Life, i, 1888-9, p. 169 (habits). 



Rhyssa Dalla Torre, Cat. Hym., iii, 1901-2, p. 482. 



Epirhyssa Schmiedeknecht, Gen. Ins., fasc. 62, 1907, p. 59. 



Rhyssa Schmiedeknecht, Gen. Ins., fasc. 62, 1907, p. 62. 



Rhyssa Ramsey, The Entom., xlvii, 1914, ]■>. 20 (habits). 



Genotype: Ichneumon persuasorms Linn. 



Rhyssa, a primitive and widespread genus, occurs both in 

 America and Europe. In North America it is found from 

 Alaska to Mexico and from the Pacific to the Atlantic coast, 

 and is also found on the island of Cuba. There are two records 

 of fossil Rhyssae being found, one in the Lower Miocene and the 

 other in the Oligocene.^^ It occurs under such a variety of 

 climates and conditions that considerable variation both in 

 color and structural characters is found. It would seem as though 

 it were trying to break up into a number of races and thence 

 to species, but its variations have not become fixed to such an 

 extent that they may be considered as permanent. Rhyssa 

 persuasoria, the oldest described species of this genus, was de- 

 scribed by Linnaeus; since there have been several new species 

 described, in some instances from a single specimen, but the 

 amount of variation is so great that it does not seem safe to 

 accept as a new species, one described from a single specimen. 



" Can. Ent. xix, 1887, p. 206. 



'2 Scudder, Tert. Insect, t. 10, 1890, p. 19. 



