164 TRANS. ST. LOUIS ACAD. SCIENCE. 



OdOntOmeruS (Anomalon) mellipes, Say.— $.— Black. Head polished, 

 with fine, shallow, not thick-set punctures, subobsolete on the vertex. Face 

 finely rugose on the disk, which projects beyond the eyes by \ their shorter 

 diameter. Clypeus scarcely as long as the flagellum of the antennae is 

 wide. Labrum truncate-triangular, rufous, with long rufous hairs. Mandi- 

 bles toothed as usual, and basally rufous. Palpi pale luteous. Antennas % as 

 long as the body, with the 1st joint of the flagellum 3 times as long as wide, 

 and the following 6 or 7 joints rather shorter, the 3d joint the longest of 

 them; the scapus black, the flagellum reddish-brown. Thorax polished, 

 with very fine, sparse, shallow punctures, the spaces on each side of the 

 two scutels with oblique stria?. Metathorax a little rugose, its carinate 

 areas complete save that the basal is confluent with the central area, which 

 thus becomes thrice as long as wide. Lateral areas angulated behind, and 

 terminating in an acute thorn directed upwards and backwards. Abdomen 

 polished, with very minute, sparse, shallow punctures. Joint 1 with a few 

 rugae and with the 2 usual carinae indistinctly traceable to the tip, 2| times 

 as long aswide and 2| times as wide behind as before, its sides straight 

 save that their extreme tip is a little constricted and the spiraculiferous tu- 

 bercle is placed § of the way to the tip. Joints 2 and 7 as long as wide, 2 

 with some close-set, transverse rugae at its extreme base ; the other joints 

 short. Dorsal surface of 7, and especially of S, concave, and 8 tapered to a 

 point acute in profile view and obtuse when viewed from above. Oviposi- 

 tor J longer than the body, its sheaths full £ wider on the terminal ^ than 

 at base. Venter excavated, of an obscure gray except at tip. Legs pale 

 rufous; the tips of the middle tarsi and the whole of the hind ones fuscous; 

 the middle tibiae twisted as usual ; the tooth on the hind femora placed § 

 of the way to the tip. Wings subhyaline slightly tinged with smoky yel- 

 low; veins black; stigma black, basally whitish. First recurrent .vein 

 slightly angulated at \ of the way to its tip ; 2d recurrent vein slightly con- 

 vex towards the tip of the wings. Length $ .38 (.34 Say) inch. Front 

 wing $ .28 inch. Ovipos. .50 inch. 



One 2 ; 6* unknown to me. Distinct from ALthiops, Cress., and 

 abdomitialis, Cress. , by its metathoracic thorns and by its wings 

 not being fusco-hyaline, and from the latter by its rufous coxa? 

 and trochanters and black abdomen. From striatus, Brulle (Eu- 

 rope), it is separated at once by the tooth on its hind thighs 



Genus XYLONOMUS, Gravenhorst. 

 This genus is very remarkable for possessing the same sub- 

 basal, oblique, connate suture on the tibia which occurs in certain 

 of the true Spiders, and which becomes a free suture in the Pha- 

 langioid Spiders — a peculiarity which does not appear to have 

 been hitherto noticed by authors. The tendency hereby exhibit- 

 ed is further exemplified in the double trochanters found through- 

 out the entire family Ichneumonida. If we can trust to Westwood's 



