4 THE ENTOMOLOGIST. 



not surrounded themselves by an air-cavity in a case, or any 

 such arrangement. Two larvae are found mining in the middle 

 of the thick parenchyma of leaves of L. polyrhiza, without 

 any indication that they are not completely wetted by water 

 and sap. 



June 16th. — In handling the newly-hatched larvae, to place 

 them separately, and in positions in which their proceedings 

 may be observed, it is seen that the larvae are completely wet, 

 but when brought out of the water they become largely dry, but 

 immediately get wet on being placed in the water again. The 

 amount of protection and the manner of it seems not very 

 different from that of the upper surfaces of the leaves of Lemna 

 (except trisnlca). When submerged these became quite wet, but, 

 reaching the surface, the water leaves them, as though they were 

 slightly greasy, and in a way to force the leaves to the surface in 

 a proper position, as soon as one bit reaches the surface. The 

 under side, on the other hand, is always wet, and carries a layer 

 of water with it when taken out. Neither the Lemna nor the 

 larva carries with it a coating or layer of air, as is the device of 

 many surfaces that repel water. At the same time a floating 

 larva creeps away under a leaf without any obvious effort, 

 whilst some force is necessary to submerge an upper surface 

 of Lemna leaf ; so that, though the water-repulsion of both 

 seems of much the same character, it is weaker in the case 

 of the larva. 



June 18th.— Larvae all in cases, of all sorts of sizes and 

 shapes ; sometimes all the pieces are cut off, and the cases are 

 portable ; sometimes one side is the under surface of a large leaf 

 of Lemna, and the case is a fixture. The pieces are of irregular 

 shape, roughly triangular, &c, often as broad as long, so that 

 no sort of larva-shaped case results. These irregular shaped 

 pieces are also of various sizes, down to small corners of leaves, 

 often sections of rootlets, &c. It is in fact somewhat erroneous 

 to call them cases ; they are really shelters, manufactured as 

 rapidly as possible from the available materials. The little 

 larvae also appear to eat freely. 



19th. — Examined several cases, and found that they con- 

 tained no air — that the larva lived bathed in the surrounding 

 fluid ; the simplest way to verify this was found to be to open 

 the case under water, when no air at all was found. 



22nd. — Several cases examined ; the larvae were found to be 

 in their second stages, and the cases now contained air. The 

 head is pale, with a faint dusky tinting ; the prothoracic plate is 

 large and very black, anal plate not tinted, and looks as if of 

 same texture as rest of larva. The larva is full 2 mm. long, 

 rather thick, large head, of fairly uniform thickness throughout 

 (0'3 mm.). The hairs are now (comparatively) much shorter 

 (II=0'08 mm.) ; they are one to each tubercle, which are now 



