28 ENTOMOLOGICAL SOCIETY 



angularly arranged. Mandibles bidentate at tips. Maxillary and 

 labial palpi 2-jointed. Antennae clavate or subclavate, variable 

 in the number of joints from 8 to 12. Prothorax usually large, 

 well developed, narrowed before or subquadrate. Mesonotum 

 usually with short, triangular, convex scapulas. Scutellum flat 

 and sometimes with an impressed cross-line before apex. Wings 

 often absent, when present with a marginal fringe, the marginal 

 vein most frequently long, linear, rarely short and thickened, the 

 postmarginal and stigmal veins usually very short ; hind wings 

 narrowed toward base, not lobed, with a distinct marginal vein. 

 Abdomen distinctly petiolated, the tip compressed into a horn 

 like point with the ovipositor exserted or subexserted. Legs 

 rather slender, the tarsi 5-jointed, the claws simple. 



The Spalangiince represent a small group in the family 

 Chalcididce . section Macrocentri, that is closely allied to the 

 Pirenince and Tridymince, and in which the occipital line is 

 usually complete, the mandibles bidentate, while the antennas 

 are never more than 1 2-jointed. 



The group is further distinguished by the very short, well- 

 defined parapsides, a distinctly petiolated abdomen, by the 

 venation, and by the apex of the abdomen being compressed into 

 a small projecting horn-like process. 



Of the five genera here brought together, the parasitism of 

 four is known : fsacratusForst. is parasitic on different Aphids ; 

 Cerocephala Westw. attacks the larvae of wood-boring beetles, 

 belonging to the family Scolytidce ; Chcztospila Westw. was 

 reared from a beetle in seed of Zea mays; while Spalangia 

 Latr. is parasitic on Dipterous larvae. 



The different genera may be distinguished by the aid of the 

 following table : 



TABLE OF GENERA. 

 Prothorax subquadrate, not or scarcely narrowed anteriorly. 



Head transverse, normal, the antennae 12-jointed, inserted far above 

 the clypeus ; marginal vein very short, . . . Isocratus Forster. 

 Prothorax long, narrowed anteriorly. 



Head tridentate with deep antennal furrows, a sharp high-pointed 

 carina between base of antennae; marginal vein long. 



Head with a long spear-like process ; mandibles very large three- 

 fourths the length of the head; antennae ic-jointed in both 



sexes,* Paralcesthia Cameron. 



Head without a long spear-like process; mandibles not large. 



Antennae in 9 > 9-> i n cT IO or n-jointed, Cerocephala Westw. 

 Antennae in 9 8-jointed ; $ unknown, . Chtztotpila Westw. 



*In Cresson's synopsis the mandibles are said to be three times, as long 

 as the head, instead of three fourths as long plainly a copyist's or 

 printer's error, but a serious one. 



