102 HYDltOCAMPA STAGNATA. 



suspicion now strengthened into certainty, as will be 

 seen by what follows. 



Mr. Jeffrey began by sending me specimens of 

 every sort of case he could find tenanted by aquatic 

 larvse — and strange and interesting enough many of 

 them were — and each fresh form was hailed as the 

 desideratum, till the appearance of the imago dis- 

 pelled our hopes. At last, on the 18th of July, he 

 bred a specimen of Hydrocampa stagnata from one of 

 three pupa-cases, all alike fastened to pieces oi. Spar- 

 ganium 9 which he had found in a brook. This gave us 

 encouragement ; but, though we most carefully scru- 

 tinised again all the cases that had been found, we 

 could detect none like these little pouches, from one 

 of which H. stagnata had emerged. 



Then it occurred to my friend — by this time feeling 

 nearly confident that I had been right in saying that 

 Sparganium would in all likelihood prove the true 

 food — to capture several moths of both sexes, and 

 confine them in a vessel at the bottom of which he 

 had arranged pieces of Sparganium, both floating on 

 water and standing erect; this he did on the 21st of 

 July, and seeing that by the 27th all the moths were 

 dead, he examined the pieces of the plant, and on the 

 under-side of one of the floating pieces found two 

 neat little batches of eggs, and forwarded them to 

 me. The larvae hatched on the 5th and 6th of 

 August, and immediately on quitting the egg-shells 

 began to eat their way into some fresh pieces of 

 Sparganium simplex, which I had ready prepared, and 

 when inside the rind mined, the pith of the plant in a 

 longitudinal direction. Being almost colourless, and 

 keeping well under water when moving from plant to 

 plant, these larvae were very hard to watch ; but I 

 was fortunately able to see one on its travels within 

 twenty-four hours of hatching, and noted that it was 

 about a sixteenth of an inch long, and that the food 

 had begun to darken its internal vessels. In twelve 

 days' time, 18th of August, I saw another larva, now 



