CHAPTER XV 



Biological Notes on the Bloodsucking Flies^ 

 W. Dwigh t Pierce 



Mr. Webb, in his lecture which follows (Chapter XVI), has given us 

 a very comprehensive view of the life history and habits of the horse 

 flies of the genus Tabanus. In another lecture we presented the data on 

 transmission of diseases by the bloodsucking flies and by reference to 

 this (see Chapter XIV) it will be seen that quite a number of genera be- 

 longing to several families of flies are concerned in disease transmission. It 

 will be the aim of this lecture to present some of the salient biological facts 

 concerning these genera so as to prepare the sanitarian for controlling 

 those species in his territory, which might cause disease. 



The insects we have especially to deal with in this lecture are the 

 sand flies of the genus Phlebotomus, in the family Psychodidae ; the horse 

 flies of the genera Tabanus, Atylotus, Haematopota, Chrysops, and 

 Chrysozona, of the family Tabanidae ; the biting flies of the genera 

 Stomoxys, Lyperosia, Haematobia, and Glossina, of the family Muscidae ; 

 and the parasitic flies of the genera INIelophagus, Lynchia, Hippobosca, 

 and Omithomyia, of the family Hippoboscidae. 



There are of course many other genera of bloodsucking flies which 

 may contain potential disease carriers. Interesting discussions of these 

 flies are to be found in the books by Hindle, and Patton and Cragg. 



FAMILY CHIRONOMIDAE 



Midges 



The little midges of this family are often mistaken for mosquitoes, to 

 which they are somewhat related. Their young are the well-known 

 blood worms in streams and stagnant pools. Of the five subfamilies 

 only one, the Ceratopogoninae, contains bloodsucking forms. The eggs 

 of Chironomidae are small and ovoid, or long and pointed at their extremi- 

 ties, and are laid either in a gelatinous string of mucus or separately. 

 The larva consists of thirteen segments, with head directed downwards, 

 and mandibles well developed. On the ventral surface of the eleventh 



* This lecture was presented October 14, and issued October 23, 1918. 



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