17 



the 1 2th of June. 1904, and on the 30th of July, 191 7, This fly is 

 probably uncommon even in the northern part of Japan and I have 

 no record of it from the southern part of the Island, excepting of a 

 female from Oshima Island (Kagoshima-Ken), which is slightly larger 

 and lighter, but it is quite the same as in the northern specimens. 



II. Diatominenra, Rondani. 

 Subg. Corizoneura, Rondani. 



Archiv. Zool. Modena, III, p. 85, 1863. 



Large or medium-sized, slightly hairy flies of brownish or blackish 

 colour, with usually hyaline or infumate wings sometimes marked with 

 black. Face distinctly arched under the antennae, broad but extending 

 only a little under the eyes, without any callosities ; on the middle a 

 large quadrate prominence, which bounds by very deep sulca especially 

 at the sides ; pubescence usually long and rather dense. Frons of the 

 female without tubercle or callus but bearing the ocellgerous elevation 

 on the vertex, usually narrow. Ocelli three ; eyes usually bare. Anten- 

 nae shorter than the head ; first joint much longer than the second 

 joint very short, usually wider than it is long ; third joint much longer 

 than the first and second together, with eight annulations of which the 

 first is broad and short, being not much longer than broad, while the 

 last one is usually conical, somewhat pointed, and bears a very few 

 minute bristle- like hairs at the tip. Proboscis long or very long, 

 bearing usually narrow sucker-flaps. 



Thorax rather round, humeri somewhat distinct, with a small not 

 distinct praealar callus between them and wing-bases. Pubescence on the 

 disc usually abundant, especially towards the sides ; pleurae densely hairy 

 except on the fore part of the meso-pleurae and sometimes of the 

 sterno-pleurae very sparsely pubescent; but there is no trace of bristles 

 jr bristly hairs anywhere on the thorax or scutellum. 



Wings hyaline or distinctly smoky, sometimes with distinct 

 markings. Venation of the normal type of the Tabanidae, but the 



