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XLVI]

This is the larva of an American fly (Fig. 215) the identity of which, until it was studied by Blanchard, was doubtful.

At an early stage the larva has the appearance represented by Fig. 216; at a later stage, that represented by Fig. 216. The former stage of the larva is called ver macaque; the latter, much larger, torcel or berne. At one time these two larval stages of the same insect were erroneously supposed to belong to different species.

Dermatobia cyaniventris measures from 14 to 16 mm. in length; it has a yellow head with very prominent brown eyes;



the thorax is of a greyish colour, the abdomen of a dark metallic blue. It is widely distributed throughout tropical America, being especially common near wooded lands. It attacks the most diverse animals. Commonly it is found in cattle, pigs, and dogs, but it occurs in the agouti, in the jaguar, in various monkeys, and in birds. It is rare in the mule, and writers have commented upon its absence from the horse. In man it has been reported from various regions of the body, namely, head, arm, back, abdomen, scrotum, buttocks, thigh, axilla. Its presence is accompanied by excruciating pains, especially at those times when the larva is moving.

Blanchard, Surcouf, and Zepeda have recently thrown a curious light on the way in which this myiasis is acquired. It would appear that on attaining maturity Dermatobia cyani-