1 88 NATURAL HISTORY OF AQUATIC INSECTS CH. 



suck the juices of leaves and the honey-dew secreted 

 by Aphides. Verdat says that they distend their 

 abdomen with blood. De Geer says that they attack 

 large, smooth caterpillars, sucking their blood. The 

 caterpillars, he adds, do not take much notice of 

 them. 1 The males love sunshine, and may be seen 

 in swarms high in the air. The females generally 

 remain at lower levels. 2 



In some countries the flies of various species of 

 Simulium have proved a serious plague by the irri- 

 tation which they cause to men, horses, and cattle. 

 In Hungary and on the lower Danube great losses 

 have resulted. The bite raises a small blister, and 

 rouses the cattle to fury. They rush about wildly, 

 rubbing their hides against rocks or trees. The 

 corner of the eye is the part of man said to be aimed 

 at. Swarms of these flies have greatly annoyed 

 certain Australian exploring expeditions. In Britain 

 the flies of Simulium are perfectly harmless. 



The pupae and flies may be found in great numbers 

 in April and May, and again in August. The Insect 

 winters as a larva, gaining maturity in spring, and 

 laying eggs, which produce the autumn brood. 



The co'Q's are laid on stems and leaves of water- 



oo 



plants, hundreds being attached together in one 

 gelatinous mass. They have a thick shell, and are 

 of a yellow colour. They are like Chironomus eggs 

 in shape, but are much less transparent. 



1 Memoires, Vol. I. p. 328. 



2 Osten Sacken, Bcrl. Entom. Zeits. Bd. XXXVII. (1892). 



