ANIMALS INJURIOUS TO FARM AND GARDEN PRODUCE. 13 



larva, which has since been studied by G. W. Miiller, Miall and 

 others. 



Reaumur refers to the larva as attacking the leaf from the under- 

 side when it wishes to make its sheath, but this is not always so, as 

 I have seen them attack the leaf from the upperside, and more 

 frequently from the edge. From time to time the larvae leave their 

 old sheaths for new ones. Measurements made of forty-eight 

 sheaths showed the largest to measure 2 Jin. by ijin., the smallest 

 i Jin. by Jin., the average being if in. by fin. 



When full-fed the larvae creep up the sides of the tank, or in 

 nature up the stem of some tall water-plant and attach their sheaths 

 well above the surface of the water. They then commence and line 

 the sheath with a silky cocoon, from which the moth issues some 

 fourteen days later. Reaumur speaks of the cocoon being attached 

 to a submerged leaf, which, I think, must be an error. 



The eggs are laid on the edges of the underside of the leaves and 

 enclosed in a transparent jelly. The larvae hatch out in July and 

 August and live through the winter in this stage. 



In the case mentioned above the larvae proved exceedingly 

 destructive to Nymphae alba, Linn., and measures had to be adopted 

 to eradicate the pest. 



Hand collecting proved a troublesome and only partly efficaceous 

 remedy, as when the leaves were disturbed many of the larvae 

 would fall to the bottom of the tanks. 



The most effective remedy was found to be an open lighted 

 lantern suspended over each tank during the night. Large numbers 

 of the moths were thus destroyed. 



THE MANGEL OR BEET FLY. 



Pegomyia betae, Curtis. 



I. INTRODUCTION. 



For many years past economic entomologists, farmers, and others 

 have noticed the spread and increasing numbers of a small dipterous fly 

 that at the present time is inflicting a very serious loss upon growers 



