106 hydrocampa stagnata. 



enough to find them waiting for a moult. On the 

 21st of May, while again removing Conferva, I found 

 two larvae less advanced than the others, of rather an 

 olive tint, and both laid up for moulting. 



The first moth appeared on the evening of the 29th 

 of June, and the second on the 6th of August. During 

 the interval my stock had been diminishing from the 

 attacks of a merciless dragon-fly larva, of which once 

 or twice I had a momentary glance, but which I 

 failed to secure until almost too late, for then only 

 two pupae remained, the last of which I sacrificed to 

 the necessity of figuring and describing, and the other 

 produced the second moth. 



This sketch of the progress of R. stagnata reared 

 from eggs on Sparganium simplex will have shown 

 that on this plant the larva is a veritable miner from 

 the moment it leaves the egg-shell until after hiber- 

 nation in the spring, when it finds itself unable to 

 mine into the young leaves of its food-plant, which 

 are then too narrow and thin for the purpose, but, 

 accommodating itself' to the changed condition of the 

 plant, it now spins parts of the flaccid leaves together 

 and lives between them, securely hidden from view. 



Its habits on Sparganium ramosum, a plant of 

 larger size, are somewhat different. This plant in 

 spring at first bends under any flowing water, but 

 soon gathering substance and strength stands erect; 

 and the larva after hibernation is still a miner, no 

 longer, indeed, eating its way longitudinally through 

 the tissues of a single leaf, but excavating large irre- 

 gular perforations through some of the inner leaves, 

 generally sparing the keel as well as the fibre at the 

 outer margins, so that, when thus ravaged, the leaves 

 can still retain their position. 



The larva keeps itself a little below the surface of 

 the water, and as the plant grows, the ravages in the 

 leaves turn blackish, and become exposed to view at a 

 distance above it, and thus afford a sure indication of 

 the larva below, generally about where the green 



