Cocoons, Nests and Eggs 



solved. The fly, it appears, was in the habit of depositing 

 its elongated eggs in clusters on the leaves of a certain 

 plant frequented by the mosquito. Now these eggs were 

 placed on the leaf in a most methodical manner. The ends 

 from which the grubs were destined to hatch were placed 

 on the leaf surface ; the ends which projected into the air 

 were covered with a sticky substance. 



When the mosquito came along to disport itself on the 

 leaf the sticky ends of the eggs adhered to its body. 

 Before long it is certain that the mosquito will become 

 hungry, and then it will seek some unfortunate human 

 being to satisfy its craving. Having found its victim, it 

 loses no time in puhcturing his skin, but at the same time, 

 probably called into action by the warmth of the human 

 body, or stimulated by perspiration, the fly grubs beat a 

 hasty retreat from the eggs. When the mosquito takes 

 its departure it leaves the grubs behind. They find the 

 puncture made by the blood-sucking mosquito and, enter- 

 ing, take up their residence in the flesh of their new-found 

 host. 



Many other insects' eggs depend on higher animals for 

 their welfare. The sheep-nostril fly lays its eggs on the 

 nostrils of sheep, and they hatch immediately they are laid, 

 and the grubs pass up the noses of their hosts, causing 

 them to sneeze in a vain endeavour to rid themselves of 

 the grubs. 



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