ENTOMOLOGY

CHAPTER XVBiological Notes on the Bloodsucking Flies 1W. Dwight PierceMr. Webb, in his lecture which follows (Chapter XVI), has given usa very comprehensive vie\v of the life history and habits of the horse:flies of the genus Tabanus. In another lecture we presented the data ontransmission of diseases by the bloodsucking flies and by reference tothis (see Chapter XIV) it will be seen that quite a number of genera belongingto several families of flies are concerned in disease transmission. Itwill be the aim of this lecture to present some of the salient biological factsconcerning these genera so as to prepare the sanitarian for controllingthose species in his territory, which might cause disease.The insects we have especially to deal with in this lecture are thesand flies of the genus Phlebotomus, in the family Psychodidae; the horseflies of the genera Tabanus, Atylotus, Haematopota, Chrysops, andChrysozona, of the family Tabanidae; the biting flies of the generaStomoxys, Lyperosia, Haematobia, and Glossina, of the family Muscidae;and the parasitic flies of the genera Melophagus, Lynchia, Hippobosca,and Ornithomyia, of the family Hippoboscidae.There are of course many other genera of bloodsucking flies whichmay contain potential disease car~ers. Interesting discussions of theseflies are to be found in the books by Hindle, and Patton and Cragg.FAMILY CHIRONOMIDAEMidge8The little midges of this family are often mistaker. for mosquitoes, towhich they are somewhat related. Their young are the well-knownblood worms in streams and stagnant pools. Of the five subfamiliesonly one, the Ceratopogoninae, contains bloodsucking forms. The eggsof Chironomidae are small and ovoid, or long and pointed at their extremities,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 22. 1918.223