WALSH DESCRIPTIONS OF N. AM. HYMENOPTERA. 73 



long as wide, 2J times as wide at tip as at the extreme base, its narrowest 

 part J of the way to the tip, gently concave from near the base | of the way 

 to the tip, where the small spiraculiferous tubercles are located, thence with 

 its sides slightly convex and scarcely divergent. Carina? only represented 

 by a shallow, narrow, dorsal excavation reaching to the middle, thereafter 

 obsolete. Joint 2 as long as wide, and twice as wide behind as before ; the 

 rest rapidly shorter and shorter. Joint 3 almost always with a dark capil- 

 lary transverse line behind the middle, and 4 almost always with one on the 

 middle. Venter excavated, longitudinally unicarinate, tinged with yellow 

 except at tip. Ovipositor scarcely half as long as the body, piceous, some- 

 times rufous ; sheaths black, basally as wide as the last tarsal joint of the 

 hind legs, and slightly tapered towards their tip. Legs pale rufous ; front 

 coxae and trochanters, middle trochanters, tips of middle coxae, and the hind 

 tarsi except generally their extreme base, all whitish ; hind tibiae, especially 

 towards their tips, infuscated. Wings subhyaline, sometimes tinged with 

 smoky yellow ; veins black ; stigma rufous edged with black, but always 

 pale yellowish at base, and rarely entirely pale except the black edging. 

 Radial area elongate, its posterior angle about 135 . Areolet with its sides 

 always converging towards the radial area, so that its anterior side is about 

 equal to either one of its two posterior sides. First recurrent vein obtusely 

 angulated, sometimes with, sometimes without a stump of a vein at the an- 

 gle; second recurrent vein gently convex exteriorly or obsoletely angulated. 

 Length $ .30-38 inch. Front wing $ -30-33 inch. Ovip. .14-. 16 inch. 



The o* differs from $ only as follows :— 1. The entire face and the cheeks 

 nearly up to the vertex are white, and the spot on the vertex is larger and 

 never absent. 2. The antennae are full as long as the body, in the flagel- 

 lum all but the extreme base of joint 10, the whole of 1 1-15, and the extreme 

 base of 16, are white (instead of joints 5-10), and its 1st joint is only 4 times 

 as long as wide. 3. The mesothorax is black above and for a short space 

 beneath the front wing, except in both cases the white markings, and the 

 rest of it is white; the hind surface of the metathorax is also white, and its 

 upper surface sometimes entirely black. 4. The abdomen is elongate-oval, 

 J longer than the head and thorax together. Joint 1 is full thrice as long 

 as wide, and only twice as wide at tip as at the extreme base ; its tubercles 

 are much larger, and behind them the sides of the joint are parallel ; and 

 joint 2 is only twice as wide at tip as at base. 5. The 4 front legs have their 

 coxae and all their trochanters white, the hind coxae have a terminal white 

 spot above, and the hind tarsi are entirely white. Length o* -30-36 inch. 

 Front wing $ .25-27 inch. 



Three % ; nine 9 . We find the % pectus white and the ? pectus 

 rufous in Mesosthenus thoracicus, Cress., also, and in many other 

 Ichneumonidce. Distinct at once from Cr. tr/descens, Cress., 

 % and Cr. soror, Cress., % by the white annulations of the anten- 

 nas % 9 and the white face and pectus % . From Cr. semirufus^ 

 Brulle 9 (N. Am., length .46 inch, ovip. .30 inch), the 9 is sepa- 

 rated by the uninterrupted orbits, by the mesosternum not being 



