372 HIPPOBOSCID.E [CH. 



suffering from chronic Surra. Only 40 camels had been out- 

 side the State and the great majority of them had been in the 

 Corps so long that they could not have been infected when 

 purchased, therefore the infection must have chiefly spread 

 within the State itself. Bikanir is about 200 miles square, and 

 there is only one small locality in which Tabanus is known to 

 occur. Leese proved that the outbreak occurred and spread 

 when the camels were grazing in the desert portion of the 

 State at least 100 miles from any fly zone. In this region the 

 only biting fly present was Lyperosia minuta Bezzi, which 

 swarmed on the animals and caused great irritation so that 

 the camels rubbed against each other in order to dislodge 

 them. It seems probable, therefore, that Surra can spread in 

 the presence of Lyperosia alone, and Leese believes that the 

 transmission is probably mechanical. 



REFERENCES. 



Austen, E. (1909). African Blood-sucking Flies, p. 160. 

 Leese, A. S. (1912). Journ. Trop. Vet. Sci. vol. vn. p. 19. 

 Montgomery and Kinghorn (1908). Ann. Trop. Med. and Parasit. vol. 



n. p. 130. 



Riley, C. V. and Howard, L. O. (1889). Insect Life, vol. n. p. 93. 

 Schat, P. (1903). Mededal. Proef station Oost-Java, 3rd ser. No. 44. 



CHAPTER XXII 



Family HIPPOBOSCIDAE (Tick-Flies). 



Description. The members of this family may be regarded 

 as Muscidae that have become adapted to an entirely parasitic 

 mode of life on birds and mammals. As a result certain 

 marked changes in structure and reproduction have taken 

 place and the flies form such a distinct group that they are 

 frequently placed in a separate sub-order, the Pupipara, 

 characterized by their viviparous mode of reproduction. The 

 Hippoboscidae may be distinguished by the following charac- 

 ters : 



