DURHAM DIPTERA. 219 



XXXI. 336. 

 336. Ceromasia, Rnd. 



1 (9). Tibiae black. 



2 (5). Arista thickened nearly to the end. 



3 (4). Thoracic stripes of unequal width ; V.4. beyond the 



angle curved. (1666. senilis, Mg.) 



4 (3). Thoracic stripes of equal width ; V.4. beyond the angle 



straight. (1665. juvenilis, Rnd.) 



5 (2). Arista only thickened for half its length or less. 



6 (7) (8). Abdomen grey and unmarked. 



332. Meigenia, Dsv. (1654. egens, Egg.) 



7 (6) (8). Abdomen spotted. (1668. parva, Mcq.) 



8 (6) (7). Abdomen with white fore marginal bands. 



1670. Dexodes (Ceromasia) spectabilis, Mg. 

 Bishop Auckland, 1 $, July, 1901. 



9 (1). Tibia? yellow. (1664. florum, Mcq.) 



337. GymnochjETA, Dsv. 



167 1. Gymnochceta viridis. 



Escomb, 1 $, May, 1897 ; Bishop Auckland, 2 $, 

 May, 1902. 



338. Exorista, Mg., and others. 



They are all Exorista except where another generic name is 

 noted. 



1 (10). Palpi black. 



2 (5). Scutellum at least partly red or orange. 



3 (4). Lower facial bristles reaching the middle of the face. 



340. Blepharidea, Rnd. 1688. vulgaris, Fin. 

 Bishop Auckland, 2 ?, Harperley, 1 ?, May-August, 

 1900-01. 



4 (3). Lower facial bristles not reaching nearly half-way up 



the face. (1674. agnata, Rnd.) 



5 (2). Scutellum entirely black or grey. 



6 (7). V.4. beyond the angle very much bent; 0.4 2 almost 



or entirely closed. 



357. Aporomyia, Rnd. 1735. dubia, Fin. 

 Bishop Auckland, 1 $, May, 1901. 



