220 SANITARY ENTOMOLOGY 



Haemogregarina sp. passes its sporogony in Glossvna palpalis but 

 its vertebrate host is unknown. 



Metazoa 

 Nemathelmmthes: Nematoda: Filariidae 



Filaria (Loa) loa (Guiyot), cause of a human filariasis, was found by 

 Ringenbach and Guyomarc'h in the Congo to pass part of its life cycle in 

 Chrysops centurionis Austen, and by Leiper in West Africa in Chrysops 

 dimidiata Van der Wulp, and C. silacea Austen. Leiper obtained a slight 

 degree of infection but development was unequal and slow in Haematopota 

 cordigera Bigot and Hippocentrum trimaculatum Newstead. He 

 obtained only negative results with Stomoxys nigra Macquart, S. calci- 

 trans Linnaeus, Glossvna palpalis Robineau-Desvoidy, Tabanus par 

 Walker, T. socialis Walker, T. fasciatus Fabricius, and T. secedens 

 Walker. 



Thus it will be seen that many of the most dangerous diseases of 

 animals and some of the most dreaded human diseases are carried by 

 bloodsucking flies, and furthermore, that the transmission is principally 

 biological, that is, the insect is a necessary intermediate host. In this 

 case the parasite invariably passes its cycle of sporogony in the inver- 

 tebrate and its cycle of schizogony in the vertebrate, if it passes through 

 such a cycle. 



A number of organisms found only in the insects are recorded. It is 

 quite possible that some of these will ultimately be linked up with 

 pathological species. Any one studying disease transmission must know 

 in advance what organisms he might encounter in the insects he is 

 studying. 



BIBLIOGRAPHY 



Anderson, J. F., and Frost, W. H., 1912. — U. S. Treas. Dept., Public 

 Health Report, vol. 27, No. 4-3, Reprint No. 99, 5 pp. 



Anderson, J. F., and Frost, W. H., 1913. — U. S. Treas. Dept., Public 

 Health Report, vol. 28, p. 833. 



Brumpt, E., 1902. — Arch, de Parasit., vol. 5, p. 158. 



Castellani, A., and Chalmers, A. J., 1913. — Manual of Tropical Medi- 

 cine, 2nd edit. 



Doer, Franz, and Taussig, 1909. — Das Pappatacifieber. Franz Deuticke, 

 Leipzig and Wien. 



Dorset, M., McBryde, C. M., Nile, W. B., and Rietz, I. H., 1919.— Amer. 

 Joum. Vet. Med., vol. 14, No. 2, pp. 55-60. 



Duke, H. L., 1912.— Proc. Roy. Soo., vol. B 85, No. B 580, pp. 378-384. 



