OF WASHINGTON, VOLUME XVIII, 1916 181 



by a chitinous substance which must be fluid at the time of 

 oviposition and which hardens upon exposure to the air" (6). 

 The fact that the mosquito serving as vector is one of the most 

 bloodthirsty species is 'also significant. Further arguments in 

 support of this view have been given by me in a previous paper 

 (5) and need not be repeated here. In short, there is no longer 

 room for doubt that the female Derrnatobia normally attaches 

 its eggs to female mosquitoes, selecting for this purpose definite 

 species with a keen appetite for blood in order that the transfer 

 of the young larva to a suitable host mav be assured. State- 

 ments as to other modes of infestation, such as the occurrence of 

 the eggs or young larvae of Derrnatobia upon foliage, must be 

 treated with suspicion until definite proof is forthcoming. 



Proof that the eggs in question are really those of Dermatobia 

 has been furnished through the rearing of the fl - from such eggs 

 by Doctor Morales. In his second paper hs announced the 

 receipt of further specimens of mosquitoes with Dermatobia eggs 

 attached. Newly hatched larvae from this material were trans- 

 ferred to rabbits and the metamorphosis was successfully com- 

 pleted. Doctor Morales had already made the attempt with his 

 first specimen, one of the eggs having hatched ten days after 

 its receipt. He placed the newly hatched larva upon the fore- 

 arm of a servant, where it moved about as if seeking a suitable 

 place of entrance. To induce the larva to pe i 'irate the skin, 

 the epidermis was slightly abraded and this at once had the 

 desired effect. Development went forward in the typical man- 

 ner, already well known, for 27 days. The patient then expressed 

 a desire to be relieved, the arm having beco.ne much swollen 

 and there being severe lymphangitis. The la vi, which already 

 had a length of 1 centime er, was extracted and transplanted to a 

 rabbit, but failed to reach maturity. Dr. P *, iro Zepeda, in 

 Nicaragua, has ) rod iced infestation with Dermatobii larvae experi- 

 mentally by ca ising human subjec s to be bit e.t by mosquitoes 

 bearing the eggs of the fly (3). He has observed the Dermatobia 

 larva leaving the mosquito while this was sucking !>!ood. Having 

 reached the skin, it at once "by an admirable instinct" finds 

 the punctured spot and enters, the subject ha ing become insensi- 

 tive to the penetration of the larva through th;3 anesthetic and 

 irritating action of the mosquito's saliva. Doctor Zepeda states 

 furthec that he has found the Dermatobia eggs attached to the 

 femora, antenna 1 and prothorax of the mosquito. 



Before leaving the subject, attention must be called to a mis- 

 leading inaccuracy in the figure published by Dr. Louis W. Sam- 

 bon (7) and repeated by Doctor Balfour (8). The e^u;s are shown 

 as attached by their sides to the belly of the mosquito, with the 



