360 



THE NOTACANTHA. 



short bristles^ whilst in the females it is elongated, 

 and furnished with six powerful lancets, adapted, 

 like those of the Gnats, for the gratification of their 

 sanguinary tastes. Unlike the Gnat, this fly produces 

 no permanent pain or swelling by its bite, although 

 at the moment it is very sharp. This, however, is 

 one of the smallest of these bloodsuckers : the species 

 of the genus Tabanus, which agree with H(2matopota 

 in th^ir general structure and habit, are of far more 

 formidable dimensions, although, fortunately for our 

 cattle, they do not occur quite so plentifully in this 

 country. Thus the Tabanus bovinus, or Ox-Breeze Fly, 

 measures nearly an inch in length, and the common- 

 est species, T. autumnalis^ three-quarters of an inch. 

 These flies are usually found in the neighbourhood 

 of woods; their flight is exceedingly rapid, accom- 

 panied by a loud humming noise, and they whirl in 

 large circles round the cattle which they have selected 

 as the objects of their attack. The Chrysops ccecu- 

 tienSj another species with splendid golden green eyes, 

 spotted with purple, rather smaller than the Hcema- 

 topota pluvialis, is found pretty commonly in meadows 

 towards the end of June, and bites both men and 

 cattle very sharply. 



From these insect tormentors of man and beast it 

 is gratifying to turn to some whose lives are passed 

 without any attacks either upon our persons or pro- 

 perty, for the next tribe which we must take into 

 consideration is the only one in the whole order of 

 Diptera which includes no injurious species. The 

 natural history of some of the commonest species is, 

 hov/ever, sufficiently interesting to make up for the 



