\ 





28 



The majority of the batches were found early in the morning between 

 6 and 7 a.m. ; if not laid at this time, they were generally found in 

 late afternoon or evening. An unfertilised female retained her egg- 

 laying power for 43 days, and it has been shown by Goeldi that fertilised 

 eggs may remain dormant in a female for 102 days, if a feed of blood 

 is withheld. A temperature of 98'6° F. appeared to have the effect 

 of shortening the life, diminishing the blood-sucking propensities and 

 destrojang the fertility of S. fasciata. 



Inbreeding experiments showed that adults which hatched from 

 eggs laid by the same mother in the same batch were fertile with each 

 other. This fact is of little importance in the case of S. fasciata, as it 

 is very abundant at Accra, but is of significance in the case of the 

 rarer species of Stegomyia, for which the avoidance of inbreeding 

 would be more difficult. 



The duration of the life-cycle can be extended under certain con- 

 ditions. In one case the egg-stage lasted from 14th June to 20th July. 

 The arrest of development of the larvae in many instances may have 

 been due to the fouling of the medium or to infection by Ciliates or 

 Vorticella. Several species of mosquitos are known to breed in salt or 

 brackish water. At Accra, Ochlerotatus irritans breeds in water 

 containing 1,400 parts of chlorine per 100,000, Culex fatigans in water 

 containing 1,600 parts and C. decens in water containing 2,000 parts 

 ( = 3"28 per cent. Na CI). Experiments showed that S. fasciata either 

 would not oviposit in a 2 per cent, salt solution, or laid eggs which 

 were rapidly killed. In several experiments with saline media ^ 

 development appeared to be accelerated, as compared with controls, 

 in tap-water. This acceleration may be a natural reaction on the 

 part of larvae and pupae to protect themselves from the drying up of 

 pools in which they normally breed. 



Lamborn (W. a.). Second Report on Glossina investigations in 

 Nyasaland. — Bull. Entom. Research, London, vi, no. 3, December 

 1915, pp. 249-265, 3 plates. 



During the latter part of March and the beginning of April, the 

 distribution of Glossina morsitans on the east side of Lake Malombe 

 was studied. Although in none of the localities visited were the flies, 

 so numerous as in the proclaimed area, yet isolated flies were found 

 over a very wide range. The distribution of G. morsitans in varied 

 types of country was well seen in the fly-belt of the proclaimed area. 

 The numbers were greatest where the thorn bushes and large trees, 

 were thickest. In studying the proportion of the sexes, it was found 

 that when the flies were bred from pupae, the numbers of males and 

 females were almost equal ; when flies were captured, the males were 

 much more numerous than the females. This is due to a difference 

 in feeding habits, and to the fact that females are more abundant 

 on the outskirts of a fly area, and when pregnant, hide themselves from, 

 the males. 



The adults were found to be attacked by a dragonfly, Orthetruni 

 chrysostigma, Burm. During May, two specimens of Mutilla glossinae 

 Turner, were reared from pupae near Monkey Bay. Since then, 54 

 males and 71 females have been reared from 1,143 pupae. There is, 

 reason to believe that M. glossinae can be bred in some numbers in the 



