DIPTEKA. 175 



what resembling the arms of a hydra, hence they have 

 been called " polype worms ;" these are often found in 

 ponds in great numbers. Their nymphs, which inhabit 

 the same element, resemble those of the gnats above 

 described, and the escape of the perfect insect is managed 

 precisely in the same manner. Other Tipulae, as, for 

 example, 



The Daddy-long-legs (Tipula olemcea), so commonly 

 met with amongst the grass in our meadows, are derived 

 from larvae that live in the ground, or are found in old 



FlG. 135. PUPA AND INSECT OF CHIRONOMUS. 



bark or rotten trees. Their nymphs are naked, breathe by 

 means of two respiratory tubes situated near the head, 

 and have the rings of their abdomen covered with little 

 spines. 



The Whame Flies (Tabanus) constitute a very for- 

 midable race, having appended to their proboscis six lancets 

 so strong as to penetrate the skin of the horse. These 

 insects, which generally make their appearance towards 

 the close of spring, are common in woods and pastures. 

 They fly with a buzzing sound, and pursue even man 

 himself in order to suck his blood. The unfortunate 

 cattle, having no means of resisting their attacks, are 

 sometimes covered with blood owing to the bites of these 

 insects; and Bruce, the Abyssinian traveller, speaks of 

 one species, before which even the lion quails. Their 

 larvas are long cylindrical maggots, tapering towards the 

 head, which is provided with a pair of hooks instead of 

 jaws. Their pupa is naked, nearly cylindrical, with hairs 



