the Egg-laying of Trichiosoma. 181 



pouch (micropylar end?). The movement occurred to 

 and fro twenty times in a minute in one case in which I 

 . counted it. In another egg it is slower and in a younger 

 egg, in which the spot is not so well developed, it occurred 

 only at considerable intervals. On investigation it appeared 

 that the brown spot is one of the eyes of the larva, quite 

 distinct, being only under the transparent cuticle of the 

 leaf; the other is invisible, being on the other side of the 

 head and can only be glimpsed from below, owing to the 

 thickness of the parenchyma of the leaf. The movement 

 is really a periodical rotation of the head of the larva. 



The movement in the earhest (April 22nd) eggs ceased 

 on May 3rd, and on May 4th the first larva hatched. The 

 young larva is very large for the size of the egg, 7 mm. lon», 

 green, with large brown (or black) eyes and a dark spot 

 in the middle of the labrum. It escapes by an irregular 

 tear in the thin cuticle, sometimes of considerable length, 

 sometimes small, so that it seems the larva could hardly 

 have got through it. 



On the 14th of May the larvae had moulted to 2nd instar, 

 the largest 15 mm. long, but not yet full-grown in that 

 mstar. They are pale, almost colourless, except for 

 intestinal contents. They become rather white and opaque, 

 and the interior obscured, by an efflorescence, which is 

 not present just after moult and easily rubs off. Except 

 for size these larvae were very hke those one is famihar 

 with on hawthorn. Exigencies of travel led to their being 

 so ill used that several reached the 3rd instar, but none got 

 any further. 



The egg all but fills up the pouch and measures 2-5 mm. 

 parallel with the length of the leaf and 2-0 mm. across, 

 the branch of the pouch towards the opening seems to get 

 more or less glued together and is sometimes quite visible, 

 in other cases cannot be made out. 



In carefully watching with a good lens the laying of 

 some two dozen eggs, the question present to me was always 

 how is the cutting actually done, is it cutting, carving, 

 tearing or what ? I concluded that it was none of these,' 

 but really the action of scissors, something hke the action 

 of a reaping- or mowing-machine, or even more closely 

 of horse-clippers. Each of the projections of one of the 

 " saws " in passing a similar projection of the other acted 

 with it as a pair of scissors cutting through the scrap of 

 tissue caught between them. In making the pocket, i. e. 



