260 TROPICAL MEDICINE AND HYGIENE 



wings, thorax, abdomen, and legs with long hairs. 

 They have no ocelli. The larvae breed in caves, crevices, 

 in walls, amongst stones, in any dark moist place where 

 the air is still and there is protection from light. Decay- 

 ing nitrogenous refuse is favourable to their development. 

 They are slower in their development than mosquitoes, 

 the eggs take about a week to hatch, the larvae some eight 

 weeks before pupation, and the pupal stage about two 

 weeks. These periods are shorter in hot weather and 

 may be indefinitely prolonged in very cold weather. The 

 flies, therefore, are most abundant during hot weather. 



The infective agent is present in the blood only during 

 the first twenty-four hours of the attack and an interval 

 of six days is required before the phlebotomus is capable 

 of infecting man. 



Trypanosomiasis is carried by Glossina of several species. 

 The larvae live in the abdomen of the female till ready for 

 pupation and then burrow into loose earth and become 

 pupae. The vulnerable periods then are limited to the 

 pupal stage and the imago, and in the case of a pupa in 

 loose earth, decayed leaves, and crevices there is t little 

 chance of its destruction. Protection of infected persons 

 and animals from a day-biting fly is difficult, and so 

 far the most successful results have attended the aban- 

 donment of places where the fly is prevalent. Systematic 

 prophylactic treatment with atoxyl is a more serious 

 matter than systematic treatment with quinine, and has 

 not been adopted on a large scale. Suitable clothing, 

 selection of places for rest, neither in boat nor near water 

 in forest country, diminishes the risks. 



Kala-azar. The general belief is that a species of 

 Cimex, C. rotundatus, is the carrier. This insect is a 

 breeder in places similar to the European bed bug, 

 Cimex lectularius. It is not conclusively proved that this 

 bug is a carrier. Donovan suggests that Conorrhinus 

 rnbrofasciatus may be a carrier, possibly acquiring the 

 infection second-hand from the bed bugs on which it is 

 believed to feed. 



