98 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 6 



under good conditions to several months, as this is the overwintering 

 stage. 



The duration of the pupal stage varies but is usually two to three 

 weeks. 



The length of the adult's life is not definitely known though the 

 flies have been observed to live several days. Those which have 

 fed on human blood exist for a longer period than those which have 

 not. Such have existed eight days before being used. There are 

 two principal broods, one in July and one in October, though some 

 are found emerging throughout the entire season. 



As far as our observations go, based on the work of the fly and the 

 anatomy of its mouth-parts these flies do not pierce but rather scrape 

 until the blood oozes through the denuded spot. At certain times 

 they bite the human skin readily. A second fly has been observed 

 to participate in lapping up the superabundance of blood caused by 

 the scraping of the first fly. 



Ill — Experiments: Last season the flies were very abundant. 

 This season they were notably rare, due principally to the flooded 

 condition of the creeks in the northern part of the state and to the 

 continued drouth in the southern part of the state. 



Turkey Creek in the southern part of the state where our breeding 

 experiments were so successful last year was entirely dry this season 

 and the rocks covered with quantities of dried pupae and larvae. 



It was not possible, therefore, to conduct as many inoculation 

 experiments as last year, due to the absence of flies and likewise to 

 the absence of incipient cases of Pellagra. 



Last year we had an abundance of flies and nine cases of Pellagra. 

 This year we had few flies and only two new cases of Pellagra. 



Six monkeys were imported direct from India for this work. The 

 almost total absence of flies in July as well as the want of a Pellagrin 

 in the proper stage prevented any successful inoculations then. 

 In the fall brood two inoculations have been made without waiting 

 for the flies to bite the monkey after having bitten the Pellagrin but 

 introducing them by maceration attended by the proper aseptic pre- 

 cautions. 



The last inoculation, • thus far, was made on a second monkey 

 on the dates of December 16, 17 and 20, using flies that had emerged 

 on the 12th and had bitten the Pellagrin on the 14th. 



Obviously sufficient time has not elapsed for the results of these 

 experiments to become apparent. 



Summing up the work of the past two years, for and against the 

 Sambon theory : — 



