XOO DURHAM DIPTERA. 



XVI. 156. 



156. Tabanus, L. 



18 (21). Very large species, 20-22 mm., dark brown with 



yellow bands. 



19 (20). Sides of the abdomen largely yellow, the dark brown 



ground not predominant. (9 I o. bovinus, L.) 



20 (19). Sides of the abdomen only slightly yellow, the almost 



velvet-black ground predominant. 



(411. sudeticus, Zlr.) 



21 (18). Smaller species, 10-16 mm., of whitish-grey colour 



with rows of whitish spots on the abdomen. 



22 (23). Male vertical triangle shining black ; female with four 



black warts above the antennae. 



(917. glaucofiis, Mg.) 



23 (22). Male vertical triangle dusted whitish grey; female 



with only the usual three black warts between the 

 eyes. 



24 (27). Antennas black. Eyes banded. 



25 (26). Large plump species with a short broad abdomen. 



912. Tabanus auhtmnalis, L. 

 Bishop Auckland, 1 $, 1 ?, July, 1899; Harperley, 

 3 ?, 28-6-02. 



26 (25). Abdomen elongated and narrow. (916. cordiger, W.) 



27 (24). Antennas yellow, or at least not all black. 



28 (29). A row of rather long forward-directed hairs on the 



vertex and posterior orbit. (915. maculicomis, Ztt.) 



29 (28). These hairs absent from the posterior orbit. 



(914. bromius, L.) 



30 (1). Hind tibiae spurred. Ocelli present. Wings banded. 



157. Chrysops, Mg. 

 Life history unknown. 



31 (36). The black shining warts on the cheeks distinctly 



separated from those on the jowls. 



32 (33). Legs all black in the male, or at most the mid and 



hind metatarsi and the base of the mid tibiae 

 brownish in the female. The black base of the 



