IIO TRANS. ST. LOUIS ACAD. SCIENCE. 



seem to vary very considerably in size, though in irritator some 

 specimens appear to be \ longer than others ; and, so far as my 

 scanty specimens show, it varies but very little in coloration. All 

 my species have as hort, robust, basal tooth on the tarsal claws. 



F|»hialt''S jrigas, n. sp. — ?. — Head with the vertex and front subgla- 

 brous and polished, the face (except the orbits) and the clypeus closely 

 punctate, subopaque, and with sparse cinereous hairs, the clypeus trun- 

 cate at tip, and slightly emarginate and depressed in the middle. Palpi 

 yellowish-white. Antenna? full i as long as the body. Thorax above and 

 below a little hairy, especially behind; polished, with fine but not dense 

 punctures interspersed, especially on the anterior lobe, with oome fine 

 longitudinal rugae. Tegulse brownish-white. Metathorax finely rugoso- 

 punctate, with two acute, lofty, subparallel carina? extending full halfway 

 to the tip, where they suddenly expand so as to enclose an obsemicircular 

 space, the excavation between the parallel carina? glabrous in the middle 

 throughout. Abdomen opaque and presenting the appearance of virgin 

 silver, excepting of course on the small glabrous and polished tip of each 

 joint, with regular, confluent, fine punctures entirely free from rugae except 

 on joint i ; these punctures gradually disappear towards the tip of the ab- 

 domen, so that the last few joints are subglabrous and polished. Joint I 

 laterally rugoso-punctate, with the usual 2 dorsal carinae lofty at base and 

 fading out at \ the way to the tip, and a lateral one lofty at tip and fading 

 out f the way to the base. A subhemispherical, highly polished excava- 

 tion on each side in the suture between the ist and 2d joints, from which 

 there proceeds an oblique, deeply impressed stria terminating in the spi- 

 racle of joint 2. A similar but much fainter excavation and stria in the 

 following suture. The usual tubercles very distinct on joints 3-5, and 

 elongate, not round. Joints 1 and 2 equal in length, each being 2£ times as 

 long as wide ; 3 a trifle shorter ; 4 shorter by \ than 2 ; and 5 shorter by \ 

 than 4, so as to be only about \ as long as either 1 or 2. Ovipositor full \ 

 longer than the body. Legs pale rufous, all the sutures a little darker; all 

 the spurs, the tips of the 4 front tarsi, the tips of the hind tibiae, and the 

 whole of the hind tarsi, a little obfuscated. Wings subhyaline, tinged with 

 smoky yellow; veins black, the radius and the extreme base of the other 

 veins pale rufous ; stigma black, 5 times as long as wide, and with its ba- 

 sal I pale rufous. Areolet rhomboido-triangular, the 2d recurrent vein, 

 which describes a regular and very convex curve, entering it i£ of the way 

 to its tip. Length 5' 1.27 inch. Front wing 9 .83 inch. Length abd. 9 

 .85 inch. Width abd. 9 .10 inch. Ovipos. 1.80 inch. 



One ? , taken on the wing in October ; 6* unknown to me. This 

 is the largest species found in North America except occidentalism 

 Cress., from which it differs in the very different proportions of 

 abdominal joints 1-5, in their not being transversely striate, and 

 in the ovipositor being black, not ferruginous, which last charac- 

 ter however is probably of but slight specific value. May possibly 



