OF WASHINGTON, VOLUME XVIII, 1916 179 



from, and used by permission of Mr. Sanders and show a pupa in 

 its cell in the leaf stem, a full grown larva, and an adult on the 

 swollen leafstem of its hostplant. 



EGG-DISPOSAL IN DERMATOBIA HOMINIS. 



BY FREDERICK KNAB, Bureau of Entomology. 



Within the last few years the statement has been made by a 

 number of writers that infestation with Dermatobia larvae occurs 

 through the intervention of mosquitoes, the eggs of the fly hav- 

 ing been found attached to the latter. At least three different 

 observers have independently reported finding mosquitoes with 

 Dermatobia eggs attached (1, 2, 3); figures have been published 

 showing the mosquito with the eggs in situ, and one author, Sur- 

 couf (4), has figured the newly hatched larva as well. However, 

 beyond the bare facts just indicated, very little of a reliable or 

 ' positive nature has been contributed to the subject. Opinions 

 as to the manner in which the eggs become fastened to the mos- 

 quito differ widely. Some assume that the mode of infestation 

 indicated is exceptional or accidental and contend that normally 

 the eggs are attached directly to the vertebrate host by the mother 

 fly. Among Venezuelans it is claimed that the fly deposits her 

 eggs upon the foliage of a special kind of tree there known as 

 "Guacimo simarron," 1 and that men and animals become in- 

 fested by contact with leaves bearing Dermatobia eggs or larvae. 

 Finally, some authors den}^ altogether the intervention of the 

 mosquito. In view of the existing confusion, it seems desirable 

 to put on record any additional data bearing on the subject, even 

 though but a repetition of what has been already made known. 



During the session of the second Pan-American Scientific Con- 

 gress in Washington this past winter, the writer had the pleasure 

 of meeting Dr. Rafael Gonzalez-Kincones of Caracas, ,who was 

 one of the first to report the occurrence of the Dermatobia eggs 

 upon the mosquito. Dr. Gonzalez-Rincones had with him two 

 specimens of mosquitoes with Dermatobia eggs attached and he 

 very kindly presented these to the writer. These specimens arc 

 of the greatest interest and their examination enables us to make 

 several deductions. In both cases the mosquito is a female 

 Pxorophora (Janthinosoma) lutzii, the same and only species defi- 

 nitely identified as bearer of the Dermatobia eggs by previous 

 writers. In both cases the eggs, eight or ten in number, form a 



1 Prof. H. Pittier of the Bureau of Plant Industry inform* me that this 

 tree is the Guazuma tomentosa H. B. K. of botanists. 



