INSECTS AND HUMAN DISEASE 153 



transmission, was bitten one night no fewer than fifty-five 

 times by a Pklebotomus fly, and, as a sequel, he contracted 

 the disease. The disease has also been transmitted to a 

 dog and a monkey by the same species of fly which is now 

 known as Phlebotomus verrucarum, so that it, at any rate, 

 must be looked upon as one of the vectors of the disease. 



A DISEASE-CARRYING BUG 



The Indian bed bug is strongly suspected of being a 

 disease-carrier, but another member of the order, Rhynchota, 

 has been recently proved so. The insect in question is the 

 South American bug, Lamus megistus, known as "Bar- 

 beiro" in the states of Minas Gaeras, Motto Grosso, and 

 Sao Paulo, and " Chupanca " in the extreme south of Motto 

 Grosso, and as the wall insect, "bicho de parede," in the 

 north of Brazil ; it also occurs in British Guiana. The bug 

 (fig. 42) is dark brown, with conspicuous black markings, 

 and is about thirty millimetres long. It is the carrier of 

 a blood parasite, Trypanosoma cruzi, from man to man, 

 and the ensuing trypanosomiasis is of a fatal nature ; in 

 Minas Gaeras whole populations are at times attacked, 

 when the children either die off or the disease assumes 

 a chronic form. 



As is invariably the case with disease-carrying insects, 

 this bug is domestic in habit, frequenting inhabited houses 

 and quickly forsaking empty ones. It lives in holes and 

 cracks in the walls, where each female lays about five 

 hundred creamy- white eggs, in batches of eight to twelve. 

 The eggs resemble those of the bed bug in being rounded 

 at one end and flattened at the other. In from twenty-five 

 to forty days the larvae emerge; at first they are light 

 coloured, but they become darker as they grow older : they 

 are ready for their first feed of blood in about a week, 

 and the second, in a fortnight to three weeks after their 

 first appearance. The larvae pass through five moults before 



