DURHAM DIPTERA. 95 



XV. 145. 



4 (1). First antennal joint as long as, or but little longer 



than the second. 



5 (6) (9). Upper side of the abdomen entirely black. 



(879. tigrina, F.) 



6 (5) (9). Upper side of the abdomen black with orange 



sides, or black with yellow side-spots or bands. 



7 (8). Wings clear tawny along the fore border till near the 



tip. Abdomen with three pairs of somewhat 

 triangular spots which successively decrease in 

 size from the base. (876. hydrodromia, Mg.) 



8 (7). Wings unicolorous. Upper side of the abdomen with 



three pairs of yellow (gold-green in fresh speci- 

 mens) side-spots of nearly the same size. 



(875. ornata, Mg.) 



9 (5) (6). Abdomen green or greenish yellow, with or without 



spots or marks. 



10 (11). Upper side of the abdomen with a black central 



stripe, which is so broad as only to leave a narrow 



yellowish green margin at the sides. 



(878. felina, Pz.) 



11 (10). Abdomen with a broad black central stripe, which 



leaves a broad green margin at the sides. 



12 (15). Uppermost branch of V.4. (V.4.a.a.) distinctly 



present; the third (V.4.b.a.) shortened or rudi- 

 mentary. 

 18 (14). Abdominal central stripe not broadened out in bands 

 on each segment. Antennae yellow or brown. 



(877. angulata, Pz.) 



14 (13). Abdominal central stripe widened out like bands on 



each segment. Antennae dark brown or black. 



(880. hydroleon, L.) 



15 (12). Uppermost branch of V.4. rudimentary,, the third 



entirely absent. (881. viridula, F.) 



146. Chrysonotus, Lw. 



882. Chrysonotus bipunctatus, Scop. 

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