DUEHAM DIPTEEA. 1 95 



XXVIII. 296. 



2 (1). Wings and X-veins almost clear ; lower outer corner of 



0.4 2 much rounded. 



3 (4). Fore femora mainly yellowish. (1558. dispar, Mg.) 



4 (3). Fore femora mainly blackish. 



5 (6). Antennae moderately long. 



1559. Ascia floralis, Mg. 

 Bedburn, 2 $, 3 ?, 7-7-02. 



6 (5). Antennas short. (1560. geniculate,, Mg.) 



297. Brachyopa, Mg. 



1 56 1. Brachyopa bicolor, Fin. 

 Bishop Auckland, 1 $, 31-5-01. 



298. Rhingia, Scop. 



1 (2). Thorax slaty blue-black. ( x 562. rostrata, L.) 



2 (1). Thorax blackish aeneous. 



1563. Rhingia campestris, Mg. 

 Common everywhere. It roams about among the 

 stalks of the herbage below the leaves. 



299. Volucella, Geoff. 



" Essentially a tropical genus." Its members act as 

 scavengers during the larval stage in the nests of the larger 

 Hymenoptera. 



1 (2). Body very hairy. Humble bee like. Scutellum with 

 marginal black bristles. 



1564. Volucella bombylans, L. 

 a (b). All black haired except the third and fourth 

 abdominal segments, which are red. 



var. bombylans, L. 

 Witton, 1 $ , 12-7-97 j Bishop Auckland, 1 5 ; 

 Shull, 1 $, 17-6-00. This variety mimics 

 Bomfais lapidarius. 



b (a). Thorax yellow haired, 

 c (f). Base of abdomen black. 



