OF PHILADELPHIA. 33 



specimen may be inspected, by the comparatively few persons 

 who have the opportunity. 



Now, although a reference to a cabinet specimen ought to be 

 considered as the duty of the describer of every animal, plant or 

 mineral, whenever such reference is at all possible, yet it never- 

 theless seems also indispensable, that a detailed description, in- 

 cluding many characters, should at the same time be given for 

 the information of the distant naturalist or traveller, in order 

 that its utility may not be limited exclusively to our compatriots. 



Amongst a multitude of short and insufficient descriptions, or 

 rather indications, we find in Turton's edition of the Systema 

 Naturae, the following notice, translated from Gmelin, of the 

 existence of a very remarkable insect. 



" CESTRUS HOMINIS. — Body entirely brown. Inhabits South 

 America. Linne ap. Pall. nord. Beytr. p. 1.57. Deposits its eggs 

 under the skin, on the bellies of the natives; the larva, if it be 

 disturbed, penetrates deeper and produces an ulcer which fre- 

 quently becomes fatal." 



This insect, for the identifying of which we have [355] mani- 

 festly to depend almost entirely on the habitat, does not appear 

 to have been observed by any succeeding writers since it was 

 mentioned by its discoverer. Humboldt, however, when occu- 

 pied with his highly interesting travels in South America, was 

 struck with certain tumors that he sometimes observed to exist 

 on the bodies of the natives of that country, and which he attri- 

 buted to the concealed operations of the larva of an (Estrus ; but 

 as he had no opportunity of verifying this conjecture by satis- 

 factory examination, he relied upon the form and appearance of 

 the tumors, with a recollection, probably, of the description 

 above quoted. 



Clarke, the best writer on this genus of insects, observes that 

 the homims is probably a spurious species, and he further states 

 that it " is, perhaps, merely an accidental deposit of (E. bovis, in 

 the human body, of which there are numerous instances."* 



So perfectly satisfied was Fabricius of the non-existence of the 

 hommis as a distinct species, that in his Systema Antliatorum he 

 has taken no notice whatever of this name and description. 



* Rees' Cyclopedia, article Bots. 

 1822.] 3 



