&56 ON A SOUTH AMERICAN 



naria of Linnaeus or some other analogous spe- 

 cies ; for, he adds, all the larvae of oestrus known, 

 live on quadrupeds of the orders Herbivora and llo- 

 dentia. 



Now, although I have not seen the perfect insect in 

 question, yet my object in this paper is to show, by the 

 aid I think of sufficient data, that there is an oestrus 

 of South America which must be added to the cata- 

 logue of the foes of our kind, fully capable of a nota- 

 ble agency in augmenting the afflictions of humanity, 

 and to prove that this species is altogether distinct 

 from bovis, to which the ingenious Clark was dis- 

 posed to refer it. 



A few days since, Dr. Harlan presented to me for 

 examination, a small animal preserved in alcohol, that 

 resembled, at first view, a parasitic worm, but, on a 

 slight inspection, it became evident that it was no 

 other than the larva of a species of oestrus ; he in- 

 formed me that he had received it from Dr. Brick, 

 who had extracted it from his own leg, during a jour- 

 ney in South America. 



Description. The form of this larva is clavate, 

 the posterior moiety of the whole length being dilated 

 and somewhat depressed ; the segments of this por- 

 tion are armed with transverse series of small, black, 

 horny tubercles, dilated at their bases, near their tips 

 rather suddenly diminishing to a filiform curved hook, 

 pointing forwards and with an acute termination; 

 these series are six in number on the back and sides, 

 placed in pairs, and three in number on the abdo- 

 men j near the posterior termination of the body are 



