NOTICE OF THE EMASCULATING BOT-FLY. 45 



which he found it associated. The doubt that exists in regard to its 

 food, shows the desirability of further study of the insect. 



Its identity with the European species has been shown by Dr. Loew, 

 in Silliman's Journal, N. S., vol. 37, p. 318. Mr. Glover, in his MS. 

 Notes on the Diptera, presents figures of it, and remarks that the fly is 

 " very common in windows in the spring." 



The structural characters of this insect have made it impossible to 

 give it proper classification. From the peculiarities that it shows it has 

 been taken by Dr. Loew as the type of a separate family, viz., Scenopini- 

 dcB. Of this family, its affinities are at present undetermined, but it is 

 thought that it may be related to Bombylidic {Diptera of North America, 

 Pt. I, 1862, p. 28). Four United States species only have been included 

 in the Scenopinidce by Baron Osten Sacken, examples of Avhich are con- 

 tained in the Museum of Comparative Zoology, at Cambridge, Mass. 

 {Catalogue of Diptera of North America, 1878, p. 97). 



The Emasculating Bot-fly. 



A larva taken from the scrotum of a striped squirrel, Tamias striatus, 

 and agreeing in all particulars to the description given by Dr. Fitch 

 of Cuterebra emasciilator, in his Third Report (page 162 of Reports 

 iii-v), was brought to me on the 13th of September, 1858, at Schoharie, 

 N. Y. A second one had been left in the squirrel, an end of which 

 could be seen, it was stated, through a small opening in the scrotum, 

 made undoubtedly for the purpose of respiration. 



The example brought me was placed upon some ground mixed with 

 sand to give it less compactness, and although seemingly quite weak 

 from having been kept for two days wrapped in paper, it buried itself 

 out of sight in the course of two hours. 



Two days later the squirrel was found where it had been left, with 

 the grub within it and alive, lying opposite to the place from which 

 the other had been taken, and with the tip of its body showing through 

 the opening. Upon enlarging the opening with the point of a knife 

 and pressing slightly, the larva slowly emerged. It was of a smaller size 

 than the first, being but about three-fourths of an inch in length. The 

 testicle in which it was located, had been entirely consumed. It was 

 given some loose ground in which it buried, but reappeared upon the 

 surface two or three times before its final burial. 



Both of the above were probably immature when obtained, for nei- 

 ther of them developed the imago. 



An alcoholic specimen of the larva, also taken from the scrotum of a 

 striped squirrel, is in the New York State collection. It measures 0.75 

 inch long by 0.36 inch broad, and shows distinctly the peculiar granulated 

 surface, the rounded ten segments, and circular mouth-parts. 



