230 HABITS AND INSTINCTS OF ANIMALS. CHAP. VII. 



frantic motions frequently express the torture which 

 they are suffering, particularly from the effects of the 

 small gadfly (CE. Bovis Lin. fig. 67. a) which bores a 

 round hole in the skin, and deposits its eggs in the 

 wound. Another species of gadfly (CE. Ovis, &) effects 

 the same purpose in the nostrils of sheep, in the inner 

 margin of which they lay their eggs ; from whence 

 the maggots (c) make their way into the head, feeding 

 in the maxillary and frontal sinuses on the mucilage 

 there produced. Our dogs are not free from their par- 

 ticular tormentors. Besides the flea, and their own pe 

 culiar vermin, they suffer dreadfully from an insect 

 called the dog-tick (Acarus Lin.), which, after being se- 

 curely fixed in their flesh, will so gorge itself with the 

 animal's blood, that it will swell from the size of a 

 pin's head to that of a small bean. 



(242.) Different species of grain, no less than of vege- 

 tables, are liable to be affected and spoiled by the depre- 

 dations of insects. Wheat, in the earliest stages of its 

 growth, is attacked by a species which devours the heart 

 or central part; so that " out of fifty acres sown with 

 this grain, in 1802, ten had been destroyed by the grub 

 in question, as early as October." * Even when laid up 

 in the granary it is not secure; for the weevil (Calandra 

 granaria Fab.) preys upon it both in its larva and its 

 perfect state. The devastation which this insect has the 

 power of committing, may be estimated from the fact 

 that a '' single pair of these destroyers may produce, 

 in one year, above 6000 descendants."f Many species 

 effect sad ravages in our fields and pastures ; among 

 these is the common cockchafer (Melolontha vulgaris 

 Fab.), which continues in its larva state for the space 

 of four years, sometimes destroying whole acres of 

 grass; and, in the year 1785, many provinces of 

 France were so beset with this animal, that a pre- 

 mium was offered by the government for the best mode 

 of their extirpation.^ The hop plant is completely at the 



* Int. to Ent. vol. i. p. 169. f ld ibid. p. 173. 



t Id. ibid, p. 180. 



