CHAPTEE XIII. 



GNATS, MIDGES, AND MOSQUITOES. 



UNDER these names are included a variety of small, 

 delicately constructed flies, the very types, in the insect 

 world, of slenderness, grace, and fragility. But fairy- 

 like elegance of form is no guarantee of gentleness of 

 disposition, and it is united, in the case of some of these 

 insects, with a persistence and hardihood in attack, and 

 a bloodthirstiness of nature, that make them some of the 

 most intolerable of pests. In this country, it is true, 

 we are now, for reasons which will appear later on, 

 tolerably free from annoyance on their part; but as 

 they are world-wide in distribution, ranging from the 

 tropics to the Arctic zone, there are many less-favoured 

 lands, in which they still exist in countless myriads, 

 and in which their extermination would be hailed, 

 whether justifiably or not, as an unmixed blessing. 

 They form a sub-section of the enormously extensive 

 order of Diptera, or two-winged flies, an order which is 

 probably responsible for the infliction of a larger amount 

 of suffering and annoyance upon human beings and 

 other vertebrate animals than can be charged upon any 

 other. At least two very distinct types of Diptera .may 

 be recognised : on the one hand, there are stout-bodied 

 and comparatively short-legged flies, with minute and 

 curiously-shaped antennae, like those of the blow-fly, and 

 on the other, slender-bodied, exceedingly long-legged 



