76 



well-preserved male. 



This species has been mixed up with C. mavis for a long time, 

 but after prolonged study I am unable to identify it with the latter 

 species. It is easily distinguished from suavis, in the female by its 

 second antennal joint not being narrower than the basal joint, by the 

 outer margin of the cross-band of the wings not being curved outwards, 

 and by the second dorsal segment of the abdomen with the black posterior 

 margin which is incised in the middle; in the male by the second 

 dorsal abdominal segment being orange yellow at about the basal two- 

 thirds not interrupted by the black median stripe, by the third and 

 fourth dorsal segments of the abdomen having a yellowish middle stripe 

 and two similar coloured spots, and by the cross-band of the more 



r J 



hyaline wings being clearly incised in the postical cell. 



Chrysops basalts varies but very little in the females, the 

 third dorsal abdominal segment sometimes having a very inconspicuous 

 smaii yellowish stripe in the middle. It may be not very common, as 

 I have only records from Akaiwa (near Otaru, Hokkaido), Niigata, 

 Onuma (near Hakodate), Ajigasawa and Owani. My captures range from 

 August 1 7th to 24th. It is well known that the female bites horses or 

 cattle. A male was taken in shrubs near a mountain-stream at Owani. 



6. Chrysops sakhalinensis, Pleske. 



Ann. Mus. Zool. Acad. Imp. Sc. St.-Petersbourg, XV, p. 472, pi. IV. 

 fig. 9, 1910. 



Blackish species with the cross-band of the wings entire and 

 reaching the posterior margin, with the apical spot beyond the upper 

 branch of the cubital fork, and with the black abdomen which has the 

 large yellow lateral spots on the first two segments and has a narrow 

 yellowish median stripe on the second to fifth segments. 



Female. Vertex and frons yellowish grey, face dusted with 

 yellow. Frontal callus large, dark brown. Facial calli shining black, 

 their prolongations very wide as they are almost connected together 



