ENTOMOLOGY

SANITARY ENTOMOLOGYmany eggs are deposited. The flies immediately return to the cow. Thelarvre migrate from the dung when about to pupate and the pupll.ria areusually found at some distance away or under the sides of the patch ofdung. The horn fly in America requires about Ii days from egg toadult. .Protection of the animal from the hom fly by the use of repellents issuggested. In this connection Graybill's bulletin on repellents shouldbe consulted. Dipping yats and the cattle dip of the Bureau of AnimalIndustry (see Chapter XXXI, p. 44~), now used in the control of theTexas fever tick, aid materially in reducing. hpm fly numbers. ....>Two practical methods are available for attacking the larvlE andpupre. One is to throw lime on the dung, but the better method is to spreadout the dung so as to favor its rapid drying or to allow a number of pigsto run with the cattle. In their efforts to obtain undigested food particlesthe pigs will effectively destroy the dung as breeding places for the fly.Tsetse FliesThe tsetse flies of the genus Glossina are among the most dreaded insectsof Africa. They are the carrier,; of three or more types of sleepingsickness, of aiJ;lo, nagana, souma, horse sickness, baleri, Ilnd othertrypanosomiases of many domestic and wild, animals. There are quitea number of species, and probably all are important, but, G. morsitansWestwood and G. palpalis Robineau-Desvoidy, are the best known. Excellentdiscussions of each of th~ important species and tables for differentiationare given in the textbooks of Hindle, and Patton and Cragg.The reproduction in this genus is very remarkable, resembling thatof the Pupipara and is prohably the result of their exclusively bloodsuckingmode of life. The female lays a single larva at a time, which isretained and nourished in the oviduct until it is full grown. After thelarva is born it at once burrows into the ground and pupates. The larvais generally of a yellowish white color and bears at its posterior extremitya pair of large dark-colored protuberances between which is a depressioninto which open the spiracles of the eighth seginent. It pupateswithin the puparium or last larval skin. The puparium is broadly ovoidin shape and by its caudal appendages affords It means of distinguishingthe species.The habitats of the various species should be rather thoroughlystudied by anyone expecting service in the African tropics. In generalthe flies are found in moist forest regions, especially along river courses,but the temperature, mois.ture, and shade requirements Seem to varyfor the different species.