90 TRANS. ST. LOUIS ACAD. SCIENCE. 



Closely allied to Metopius both in coloration and structure, but 

 differs by the facial swelling not being buckler-shaped nor acutely 

 declivous all round, by the rounded scutel, by the small areolet, 

 by the 2d recurrent vein being more or less biangulated instead 

 of perfectly straight, and by bulla? C and D being distinctly sepa- 

 rated. Allied to Exochus, Grav., Polyrhabdus, n. g., and Or- 

 thocentrus, Grav., by the facial swelling ; but differs by the cheeks 

 not being at all inflated, by the front wings being set on behind 

 the middle of the thorax, by the constricted abdomen, and by many 

 other characters. Gravenhorst, in his description of the genus 

 Orthocentrus, has said that the ovipositor is erect (erectus), by 

 which, of course, he means that it is directed upwards, or exactly 

 the reverse to that of Catocentrus. Brulle has made the ridicu- 

 lous mistake of translating "erectus" by the French word "droite" 

 (straight), thus confounding "erectus" and "rectus" (Hym. p. 

 115). The position of the ovipositor, whether erect or oblique, 

 or pointed downwards, is, however, sufficiently indefinite and 

 variable character by which to define a genus ; for I find that in 

 different specimens of one and the same species (e.g. Cylloceria 

 \_occidentalis, Cress.]) the ovipositor is sometimes directed straight 

 upwards, owing to the retraction of the terminal dorsal joints, 

 sometimes directed obliquely backwards in the usual manner. 



CatOCeiltliruS pllilailthoides, Walsh [Trans. Am. Ent. Soc. ii. p. no]. 

 — cf .. — Black. Head with the vertex subglabrous and polished; front 

 and face closely and finely punctate ; the face bearing on its disk two large, 

 roundish, subcontiguous, yellow spots, transversely arranged. Clypeus 

 truncate and rather coarsely rugose. Mandibles and palpi piceous. An- 

 tennae § as long as the body, brown-black, the flagellum beneath dull 

 rufous, and the 1st joint of the scapus laterally and beneath yellow. Tho- 

 rax subpolished, finely and closely punctate, the punctures finer and more 

 sparse beneath. Metathorax with the two carinate lateral areas distinct 

 and divided each by cross-carinse. The other areas obsolete. Under the 

 tip of each humeral suture a triangular yellow spot. Scutel with a large, 

 subquadrangular, yellow spot, rather wider in front than behind, and with 

 its four angles, especially the front ones, considerably prolonged ; a trans- 

 verse yellow line behind this spot. Abdomen basally truncate; the angles 

 acute and a little prolonged; joint 1 oblong and flattened, $ \ and $ \ 

 longer than wide, o* \ and $ \ wider behind than before, laterally a little 

 concave, the concavity greatest J of the way to the tip; the usual two ca- 

 rinas well developed on it but fading out towards its hind edge; the joint 

 itself glabrous and polished between these carina?, elsewhere slightly ru- 

 goso-punctate and polished ; its terminal J yellow. Joints 2-5 finely and 



