84 



mammalian blood was recognised in 15, nucleated red cells in four; 

 one fly contained both nucleated and non-nucleated red cells ; in 

 32, blood in a more or less digested condition was seen ; while 15 had 

 either not fed or the detritus was not recognisable. 



" It seems possible that a little water may be taken, as the flies 

 have been observed at the edges of puddles and apparently drinking. 

 Kinghorn has observed the same thing with G. palpalis on the shores of 

 Lake Tanganyika. If a moistened sponge or blotting paper is placed 

 in a bottle with captive flies, they will settle on it and thrust in their 

 proboscides. I have not been able to prove by supplying coloured 

 fluids and subsequently dissecting the flies that fluid is actually absorbed. 

 Exactly the same thing was observed with slices of ripe water-melon, 

 but again it could not be demonstrated that food was taken up. Flies 

 placed in bottles with Sphingid larvae died of starvation, and were 

 never seen to take anything but the most perfunctory interest in the 

 caterpillars. 



" A gecko which was placed in a cage of flies caught and devoured 

 the insects. Experiments were also made with a monitor, which was 

 placed in the double bottom of a cage made of gauze in such a manner 

 that it was incapable of movement. The flies in the cage attempted 

 to feed, but only one succeeded in doing so, thrusting in its proboscis 

 in the region of the head. The animal was then killed and a cut section i 

 was offered to the flies, when several readily gorged themselves/' 



In the Gold Coast, it was found by Simpson (144) that the proportion 

 of mammalian to non-mammalian blood imbibed varies widely 

 according to the species of Tsetse-fly. G. morsitans seemed to be much 

 more dependent on mammalian blood than did G. palpalis, while 

 the chief food of G. tachinoides appeared to be reptilian blood, and that ; 

 of a large bat which abounds on the banks of the River Volta. The 

 small percentage of reptilian blood found in G. morsitans form 

 submorsitans may be due to lack of opportunity and not to preference, 

 since in the open country where this form abounds a reptilian fauna : 

 is practically non-existent. 



The work of the Luangwa Sleeping Sickness Commission terminated 

 in 1912, but in the following year the investigation into the bionomics 

 of Glossina morsitans was continued by Mr LI. Lloyd at Ngoa, " in the 

 Mpika Division, on the high ground of the Congo-Zambezi watershed." 

 Some details extracted from a paper (89) published by Mr. Lloyd 

 in 1914 of an important series of experiments carried out in the 

 course of this later work are given below. 



" INFLUENCE OF VARIOUS BLOODS ON BREEDING CAPABILITIES. In 

 the method which was adopted a definite number of freshly caught; 

 female flies were fed on goats, monkeys, fowls, ducks and chameleons. 

 In most of the experiments the flies were kept in the usual type of fly 

 bottle, four females and two males in each. A few of the series were 

 kept in large wooden cages with fronts of mosquito muslin. Records 

 were taken of the length of life of each fly in captivity and the numbers 

 of pupae and aborted larvae which were deposited ; each pupa was 

 also measured. Nineteen experiments were commenced, of which 13 

 were completed." 



Details of the results of these experiments are shown in tabular form, 

 and in the "Summary and Conclusions" at the end of the paper: 

 the author writes : " Reptilian blood is not suitable to G. morsitans 

 as a continued diet. Mammalian blood has a slight advantage over: 

 avian as a diet, and this is shown by the larger average size of the pupae. 



