WALSH — DESCRIPTIONS OF X. AM. HYMENOPTERA. IO9 



of all 6 legs also whitish, except that the exterior surface of the middle 

 tibiae and tarsi and all the tarsal tips and sutures are obfuscated, and that 

 in the hind tibiae the terminal i is dusky and there is an infuscation ex- 

 ternally near their base. Wings hyaline; veins black, paler on the post- 

 costa; stigma black, 4 times as long as wide and whitish on its basal \. 

 Areolet rhomboido-triangular, the recurrent vein entering it in the middle 

 below, and with a peduncle half longer than the triangle itself. A faint, 

 brown cloud in the inner angle of the radial area. Length 9 .55 inch. 

 Front wing 9 .40 inch. Ovipos. .70 inch. 



One ? ; S unknown to me. Allied to persuasoria^ Linn., of 

 Europe, Canada, and the Rocky Mountains, and also to albo-mac- 

 ulata. Cress. ; but is distinguished at once from both by the very 

 different markings of the thorax and abdomen, and by the meso- 

 and meta-sternum being rufous, not black. From Nortoni^ Cress., 

 it is at once structurally separated by the 2d recurrent vein enter- 

 ing the areolet in the middle of its posterior side, and not at the 

 apex as in lunator and atrata, and by the white orbits being en- 

 tirely interrupted opposite the antennae, and not merely emargin- 

 ate there. Atrata^ Fabr., lunator^ Fabr., nitida^ Cress., l(^vi- 

 ^ata^ Br., marginalis,, Br. (hab. unknown), and terminalis^ Br. 

 (Chili), have no white markings either on the thorax or abdomen, 

 and otherwise are entirely unlike. I suspect that these 3 species 

 with white markings on the thorax and abdomen, viz. persuaso- 

 ria^ albo-fnaculata, and humida, are all distinguished from the 

 others by having a rhomboido-triangular, not triangular, areolet ; 

 and in that case they may conveniently form a separate subgenus 

 to which the name of Pararhyssa may be given. Epirhyssa^ 

 Cress., which has no areolet at all, has a coloration very similar 

 to that of Rhyssa proper. 



\^Atrata, lunator {j=lcevigata (j*), Nortoni, and nitida, all belong to 

 the genus Thalessa, Holmgren ; while persuasoria, albo-maculata, humi- 

 ■da, and canadensis, belong to Rkyssa proper. — Crksson.] 



Genus EPHIALTES, Grav. 

 In this genus, which has a rhomboido-triangular areolet, the 

 bulla A is small, often subobsolete, occasionally obsolete, and is 

 placed on £he same cross-vein as B, but immediately adjoining 

 the radial area, and is separated from B, which is located near 

 the other end of its cross-vein by a considerable space. The other 

 bullae are all present and normally located, except that C and D 

 are verj- wide apart, and E is'generally closer than usual to the an- 

 ^leof the ist recurrent vein. Unlike Rhyssa, Ephialtes does not 



