LARVAE OF MAY FLY. 51 



an immensity of harm. They fasten on the 

 egg, pierce them with their sharp nippers, 

 and they turn white and dead in an instant. 

 The Messrs. Ashworth, of Galway, report 

 that, in one year they deposited 70,000 

 salmon ova in a small pure stream adjoining 

 a plantation of fir-trees, and these ova they 

 found to be entirely destroyed by the larva 

 of the May-fly. More evidence on this 

 point can be found in " Life in Nor- 

 mandy/' 



The larva of the dragon-fly is also a 

 destructive pest of the waters, and has been 

 justly called the river tiger. I show speci- 

 mens of the river tiger, which Mr. Allies 

 caught in a salmon's nest in the river Teme, 

 in "Worcestershire. 



There are other insects which eat the 



