. Handbook of medical entomology. Insect pests; Insects as carriers of disease; Medical parasitology. Filariasis and Mosquitoes 179 the United States, and as far south as Brisbane in ; In some sections, ftdly 50 per cent of the natives are infested. Labredo (1910) found per cent infestation in Havana. The larval forms of Filaria bancrofti were first discovered in 1863, by Demarquay, in a case of chylous dropsy. They were subse- quently noted vmder similar conditions, by several workers, and by Wticherer in the urine of twenty-eight cases of tropical chyluria, but in 1872 Le
. Handbook of medical entomology. Insect pests; Insects as carriers of disease; Medical parasitology. Filariasis and Mosquitoes 179 the United States, and as far south as Brisbane in ; In some sections, ftdly 50 per cent of the natives are infested. Labredo (1910) found per cent infestation in Havana. The larval forms of Filaria bancrofti were first discovered in 1863, by Demarquay, in a case of chylous dropsy. They were subse- quently noted vmder similar conditions, by several workers, and by Wticherer in the urine of twenty-eight cases of tropical chyluria, but in 1872 Lewis foimd that the blood, of man was the normal habitat, and gave them the name Filaria sanguinis hominis. The adult worm was found in 1876 by Bancroft, and in 1877, Cobboldgave it th&n&m&Filaria bancrofti. It has since been found repeatedly in various parts of the lymphatic system, and its life-history has been the subject of detailed studies by Manson (1884), Bancroft (1899), Low (1900), Grassi and N06 (1900), Noe (1901) andFiillebom(i9io). The larvae, as they exist in the circulating blood, exhibit a very active wriggling movement, without material progression. They may exist in enormous numbers, as many as five or six hundred swarming in a single drop of blood. This is the more surprising when we con- sider that they measure about 3oo[ji. x 8[a, that is, their width is equal to the diameter of the red blood corpuscle of their host and their length over thirty-seven times as great. Their organs are very immature and the structure obsctire. When they have quieted down somewhat in a preparation it may be seen that at the head end there is a six-lipped and very delicate prepuce, enclosing a short "fang" which may be suddenly exserted and retracted. Completely enclosing the larva is a delicate sheath, which is considerably longer than the worm itself. To enter into further details of anatomy is beyond the scope of this discussion and readers interested are
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