208 NATURAL HISTORY. [CH. XII. 



If, however, *ve recollect the boldness with which 

 the oestrus of the horse enters the intestine of that 

 animal, we shall not be astonished to find that a fly, 

 as full of care and foresight for its young, should, 

 with equal courage, enter the nostril of the deer. 

 According to Reaumur, the creature boldly walks 

 into the cavities, and proceeding to the extremity, 

 comes at once on the fleshy purses at the root of the 

 tongue : in these the female fly deposites her eggs, 

 and leaves them in a matrix furnished with a supply 

 for every want. 



Humboldt, Bonpland, and Gmelin have discovered 

 a species of gad-fly which attacks min. It is a na- 

 tive of South America, and is about the size of a 

 common house-fly. It deposites its egg under the 

 skin of the abdomen, where it forms a swelling of 

 the nature of that on oxen, and other animals, in 

 which the grub remains for six entire months. If 

 molested, it sinks deeper and deeper, and, creating 

 ulcers or inflammation, often causes death. 



CHAPTER XII. 



Ichneumon-fly Deposites its Eggs in the Bodies of other living In 

 sects Thirty or Forty in the Body of a Caterpillar Dragon-fly Its 

 Voracity Ferocity. 



To the numerous tribes of Ichneumons is allotted 

 by nature the task of restraining the superabundance 

 of the rest of the insect world. They were called 

 by the more ancient authors Muscce tripiles, on ac- 

 count of their abdomen being terminated by an ovi- 

 positor, composed of three hair-like pieces, or Muscce 

 vibratorice, from their habit of constantly vibrating 

 their antennae or feelers. 



The most interesting portion of their history is 

 the mode in which they are propagated. Other in 



