black spot ; seventh segment with numerous longer stiffer black hairs 

 all about the middle, sometimes the fifth and sixth (or even slightly 

 the extreme base of the fourth) segments bear a few similar black hairs 

 about the middle near the base. Genitalia with a pair of greyish 

 brown or brownish black two-jointed lamellae, of which the basal joint 

 is orange beneath, and the subquadrate widened end-joint has an orange 

 end or is wholly orange, bearing pale yellow hairs at the apical lower 

 margin. 



Length : 14-15 mm. 



This species varies but very little in width and in intensity of 

 the dorsal black stripe down the abdomen ; in colouring of the palpi of 

 the male, and in the amount of the short black bristles on them in 

 both sexes ; in the colouring of the antennae, and in the amount of 

 the black hairs or bristles on the two basal joints ; in the amount of 

 the black pubescence on the tibiae ; and in the size of the middle 

 blackish spot on the belly. 7". distinguendns is very closely allied 

 to the most reddish form of tropicus, but it may be distinguished by 

 its still more reddish abdomen, by the less black pubescence, and tiny 

 bristles on all the tibiae, by its larger less black-bristled palpi, and by 

 its eyes with only two bands in the male. 



This fly does not occur throughout Japan, but its occurence is 

 restricted in the northern parts, Hokkaido and Sakhalin, according to 

 my investigation of Prof. Matsumura's large collection and mines. It 

 may appear only in July and August, and the female usually attacks 

 horses or cattle, but apparently not very violently, while I found her 

 bite rather severe, although not painful. 



In Japan, this species is usually known as Tabanus tropicus, 

 Meig., but it is a quite mistake, and it must be corrected as dis- 

 tingnendns. I carefully examined a number of specimen determined 

 by Prof. Matsumura as tropicus, and I found two distinct species in 

 them, many of which were, no doubt, T. distinguendiis, and others 

 may be a reddish form of T. tropicus. 



