236 DTTEHAM DIPTEBA. 



XXXI. 416. 



35 (36). The second abdominal segment with two central hind 



marginal bristles. (!873. hcemorrhoidalis, Mg.) 



36 (35). The second abdominal without the two central hind 



marginal bristles. 



37 (38). The black frontal stripe wider than one of the frontal 



orbits. (1874. mirus, Rnd.) 



88 (37). The black frontal stripe equal in width to one of the 

 frontal orbits. 



1875. Sarcofihaga cruentata, Mg. 

 Hesleden, 2 $ and 1 $, August, 1900. 



424. Metopia, Mg. 

 The known larvae are parasitic in the larvae of sand-wasps. 



1 (10). Legs black. ■ 



2 (3). Frons silvery in front, black behind ; abdomen 



spotted. (1888. leucocephala, Rossi.) 



3 (2). Frons silvery in front and behind. 



4 (7). Abdomen with black central stripe and black bands. 



5 (6). Abdominal bands notched. (1886. campestris, Fin.) 



6 (5). Abdominal bands straight. (1889. amabilis, Mg.) 



7 (4). Abdomen spotted. 



8 (9). Abdominal spots distinct, three each on the second 



and third segments. (1887. argyrocephala, Mg.) 



9 (8). Abdominal spots indistinct. (1890. argentata, Mcq.) 

 10 (1). Femora orange. (1891. forficulce, Newp.) 



Sub-Family Dexin^. 

 Life history unknown. 



430. Dexia, Mg. 



1 (6). The keeled ridge in the middle of the face very 



prominent, reaching to the base of the antennae 

 and slightly dividing them. 



2 (5). Legs wholly or mostly yellow. 



3 (4). Abdomen translucent orange with black bands, and, 



in the male, with an interrupted central stripe. 



(1899. vacua, Fin.) 



