422 LEPIDOPTERA CHAP. 



them closed and functionless. After this brief period of mining 

 life, the larva moults and then constructs a habitation by cutting 

 a piece out of a leaf, and fastening it to the under side of another 

 leaf; it is thus provided with a habitation, but it is one into 

 which the water freely enters, and the respiratory apparatus 

 remains in the state we have described. The Insect passes 

 through several moults, and then hibernates in the water. On 

 its revival in the spring a change occurs, and the larva constructs 

 a portable, or we should rather say free, habitation out of two 

 large pieces of leaf of lens-shape, fastened together at the 

 edges ; but the larva has some method of managing matters so 

 that the water can be kept out of this house ; thus the creature 

 lives in air though immersed in the water. A correlative change 

 occurs in the structure of the skin and tracheal system. The 

 former becomes studded with prominent points that help to 

 maintain a coat of air round the Insect, like dry velvet immersed 

 in water ; the spiracles are larger than they were, and they and 

 the tracheal tubes are open. One or two moults take place and the 

 creature then pupates. There is a good deal of discrepancy in 

 the accounts of this period, and it seems probable that the pupa 

 is sometimes aerial, sometimes aquatic. Buckler's account of the 

 formation of the case shows that the larva first cuts off, by an 

 ingenious process, one piece of leaf, leaving itself on this, as on 

 a raft : this it guides to a leaf suitable for a second piece, gets 

 the raft underneath, and fastens it with silk to the upper portion, 

 and then severs this, leaving the construction free ; afterwards the 

 larva goes through a curious process of changing its position and 

 working at the two extremities of the case, apparently with the 

 object of making it all right as regards its capacity for including 

 air and keeping out water. He believes that Reaumur was 

 correct in his idea that the larva regulates the admission of air 

 or of water to the case in conformity with its needs for respiration. 

 Miiller calls special attention to the great changes in habit and 

 in the structure of the integument during the life of this larva ; 

 1'Ui the reader will gather from what we relate as to various 

 terrestrial Lepidopterous larvae, that these phenomena are not 

 very dissimilar from what frequently take place in the latter; a 

 change of h.iluts ;it some particular moult, accompanied by great 

 changes in the integument, and even in the size of the stigmata, 

 being of frequent occurrence. 



