No. 2320. 



TRIBE ACOENITINJ—CUSUMAN AND ROHWER. 



606 



Biological habits. — The members of this genus are parasitic on wood- 

 borers, both hymenopterous and coleopterous. 



Generic cliaracters. — Head transverse, not especially widened be- 

 hind the eyes; clypeus distinctly separated, inflexed at apex, with a 

 median tooth; malar space rather long; face flat; eyes and ocelli 

 moderate; antennae about tv/o-thirds as long as body, filiform, 

 attenuate apically. Thorax stout, oblong, weakly arched above; 

 notauli deep, complete, meeting on disk of mesoscutum, prescutmn 

 prominent; prepectal carina nearly obsolete except briefly below; 

 propodeum with more or less distinct apical, median, and lateral 

 carinae, spiracle placed much before middle, long oval to nearly 

 round; areolet, when present, oblique trapezoidal and petiolate, 

 frequently absent; legs, especially posterior, long and rather slender, 

 with hind basitarsus fully as long as remaining joints combined, apical 

 joint much shorter than second, claws simple. Abdomen clavate; 



IlG. 1.— COLEOCENTKUS OCCTDENTALIS, SiDE VIEW OF ABDOMEN; O, FEMALE; b, MALE. 



first tergite with spiracle much before middle; dorsal carinae developed 

 only at base; last tergite long and scoop-like or trowel-shaped; last 

 abdominal spiracle in female very large oval; ovipositor usually 

 slightly shorter than body, occasionally as long, and strongly com- 

 pressed. 



The male is much less robust than the female, especially in the 

 abdomen, which is slender throughout; the face, scape, and front 

 and middle legs are paler than in the female; the sheaths of the 

 genitalia are very large and obliquely truncate at apex; the last 

 abdominal spiracle is normal. 



Specific cliaracters. — The most conspicuous specific characters 

 are found in the color and color pattern of the body, the presence or 

 absence of the areolet in the front wing ; the form of the clypeus ; the 

 color of the wings and legs, especially the coxae and hind tarsi; the 

 form of the propodeal spiracle; the comparative proportions of the 

 first tergite; and the size of the ocelli. This set of characters serves to 



