28 LEUOANIA STRAMINEA. 



it remains on its food-plant and hides itself by day 

 under and amongst the mingled leaves, and comes forth 

 at night to feed ; from the structure of the prolegs and 

 their terminal discs, it is enabled to obtain a firm 

 footing on the smooth surfaces of the reed stems and 

 leaves, without any danger of being blown off, or 

 falling into the water over which it must be often 

 moving. 



The habits of the rest of the genus lead me to sup- 

 pose that the larva is hatched in autumn and hyber- 

 nates while yet small ; I have had individuals no more 

 than half an inch long sent me at various dates from 

 the end of April to the beginning of June, the growth 

 of the reeds probably influencing the rate of their deve- 

 lopment, but I found that when once they had begun 

 to feed, they took about five weeks to attain full 

 growth ; larvae which were ichneumoned lingered on 

 longer, up to the time of the appearance of the first 

 specimens of the imago. 



The larva in its immature state, when half an inch 

 long, was very slender, of a dull greyish-brown colour, 

 with an almost blackish dorsal line, and several faint 

 lines along the sides, by the arrangement of which 

 one identified it readily enough as a true Leucania ; 

 afterwards, at each moult, it became a little paler and 

 brighter coloured, its pattern of longitudinal lines and 

 stripes remaining relatively the same. 



When full-grown it measured one and five-eighths 

 to one and three-quarters inches in length, slender, 

 and tapering a little at each end, especially towards 

 the head, which was the smallest segment. It was 

 tolerably cylindrical, the ventral prolegs rather long 

 and well developed, the extremity of each furnished 

 with a circlet of sharp hooks, the anal pair being 

 usually extended behind in the line of the body, and 

 the others often appearing a little sprawling according 

 to the exigence of position; the head was slightly 

 flattened above, and the antennal papilla? well deve- 

 loped, projecting forwards in line with the head and 



