1«2 



Subg. Atylotus, Ost.-Sack. 

 Mem. Boston Soc. Nat. Hist., II. p. 426, 1876. 



This is a convenient subdivision of the gigantic genus Tabanus, 

 and is an indistinct subgenus more than Tkerioplectes. 



Eyes more or less pubescent, in life with a single slight cross- 

 band or with a few irregular shifting spots. Head rather large, very 

 convex anteriorly and concave posteriorly, without any ocellar tubercle ; 

 frontal callosities pre ent or wanting. In the male, the difference in 

 size between the large and small facets is considerable, though it is not 

 so very much as in some species of Tabanus fsens. str.). The wings 

 hyaline ; the upper branch of the cubital fork, knee-shaped at the base, 

 with a recurrent veiniet or a tendency to emit a stump of a veinlet; 

 first posterior cell broadly open, never closed. 



I have made the above difinition of the Subgenus Atylotus 

 after consulting Osten Sacken, Brauer, and Venal!, but it is very in- 

 complete as I have had only a few specimens to hand from the world. 



The Japanese species may be easily distinguished from any 

 others of the inclusive genus Tabanus, by their mealy appearance, 

 total absence of ocelli, two small roundish frontal calli (which are 

 sometimes wanting), more or less pubescence eyes, orange antennae, 

 and by the recurrent veinlet near the base of the upper branch of the 

 cubital fork, though this last character is said to be occasionally absent. 



At present we have only five species throughout Japan, as tabu- 

 lated below : 



Key for Species. 



I. Frontal stripe with two small separated callosities. 



2. Abdomen brownish orange with a broad blackish stripe ... 



fufrus, Meigen. 



22. Abdomen blackish grey. 



3. Abdomen without yellowish marking at sides 



— rusticus, Fabr'cius . 



