SOME HUMAN PARASITES 287 



commonly affected. Both species are indigenous to Central 

 and South America, and are known as " Ver macaque " in 

 Cayenne and Mexico ; " Ura " in Brazil ; " Torcel " in Costa 

 Rica ; and " Gusana peludo " or " Muche " in New Grenada. 



From the figures (84 and 85) it will be seen that the 

 young larvae are roughly of the shape of a comma, and are 

 strongly armed with a formidable array of spines. From 

 time to time these maggots had been removed from the 

 tumours which they made in the flesh of those whom they 

 attacked, though how they got there was unknown. The 

 adult flies had never been seen, and it was conjectured that 

 their eggs were laid in clothing, and that the larvas, on 

 hatching, penetrated the human skin a feasible conjecture, 

 no doubt, in the case of properly clothed Europeans, but 

 one that hardly applies to natives, who wear little more 

 than their birthday clothes. 



Quite recently light has been thrown on this much- 

 debated point. In 1900 Blanchard described some large 

 eggs, which he had found arranged in bundles and attached 

 to the ventral side of the abdomens of certain Central 

 American mosquitoes. In 1910 Morales of Costa Rica 

 discovered that the eggs were those of Dermatobia, he 

 stated that they were laid directly on the abdomen of the 

 mosquito, which then transported the larvae to their host. 

 As the bot fly is the size of a blue-bottle and the mosquito 

 is a small, frail creature, the statement seemed incredible, 

 in spite of the fact that in 1912 Tovar of Venezuela, by 

 placing specimens of the blood-sucking mosquito, Jan- 

 thinosoma lutzi, carrying Dermatobia eggs (fig. 86), on 

 various animals, succeeded in producing tumours, which, 

 after eleven days, were found to contain larvae of the fly. 

 A short time afterwards, however, Rincones of Caracas 

 announced that the bot fly is in the habit of ovipositing 

 on leaves, in damp places, frequented by Janthinosoma 

 lutzi. He said that the eggs are covered with an adhesive 

 cement, but are only fixed lightly to the leaves ; moreover, 



