CH. XVI.] DIPTEROUS INSECTS. 237 



from the region of Mehadia, but according to others 

 from Turkey. Its approach is the signal for uni- 

 versal alarm. The cattle fly from their pastures, 

 and the herdsman hastens to shut up his cows in the 

 house, or, when at a distance from home, to kindle 

 fires, the smoke of which is found to drive off this 

 terrible assailant. Of this the cattle are sensible, 

 and, as soon as attacked, run towards the smoke, and 

 are generally preserved by it. 



How beautiful a picture of rural quiet and repose 

 is given by the poet of the Seasons, of the shepherd 

 and his herds during the sultry heat of the sum- 

 mer's sun. 



" Amid his subjects safe 



Slumbers the monarch swain ; his careless arm 



Thrown round his head, on downy moss sustained. 



Here laid his scrip, with wholesome viands filled ; 



There, listening every noise, his watchful dog." 



And with what contrast does he proceed to de- 

 scribe the confusion produced by the approach of 

 some of the insect tribes. 



" Light fly his slumbers, if perchance a flight 

 Of angry gadflies fasten on his herd. 

 That startling scatters from the shallow brook, 

 In search of lavish stream. Tossing the foam, 

 They scorn the keeper's voice, and scour the plain 

 Through all the bright severity of noon. 

 While from their labouring breasts a hollow moan 

 Proceeding nms, low bellowing round the hills. 

 Oft in this season too, the horse, provoked, 

 While his big sinews full of spirit swell. 

 Trembling with vigour, in the heat of blood, 

 Springs the high fence, and o'er the field effused 

 Darts on the gloomy flood withs teadfast eye, 

 And heart estranged to fear." 



The insects which produce so much confusion 

 among cattle are generally termed gadflies and 

 breeseflies, but the application of these names is 

 by no means fixed, either to the species of insects, 

 or even to the nature of their attacks. Thus, some 

 species of the genus CEstrus, which deposite their 



