1872.) 249 
it will eat, and is sometimes found on, Phalaris arundinacea, as well as on other 
coarse grasses growing amongst reeds in wet places; 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 abdominal legs, 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 suppose that the larva is hatched 
in autumn, and hybernates whilst 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 develop- 
ment, but I found that, when once they had begun to feed, they took about five 
weeks to attain full growth; ichneumoncd larvee lingered on longer, up to the time 
of the appearance of the first specimens of the imaygo. 
The larva in its immature state, when half-an-inch long, is 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 identifies it readily enough 
as a true Leucania; afterwards, at each moult, it becomes a little paler and 
brighter coloured, its pattern of longitudinal lines and stripes remaining relatively 
the same. 
When full-grown it measures 13 to 1} inches in length, slender and tapering a 
little at each end, especially towards the head, which is the smallest segment ; it is 
tolerably cylindrical, the abdominal legs are 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 is slightly flattened 
above, and the antennal papilla are well developed, projecting forwards in line with 
the head and body ; the skin is remarkably smooth, the segmental divisions being 
scarcely indicated, chiefly in fact, by fine wrinkles forming themselves when the 
larva bends itself round, in the graceful postures it assumes, when actively en- 
gaged in feeding. 
The ground colour of the back and sides is brownish-ochreous, but, with the 
exception of a stripe on either side the back, and another again lower down, this is 
thickly covered with minute, wavy, linear, greyish freckles; the dorsal line is of 
dark grey, sometimes blackish grey, having a fine central pale thread; the sub- 
dorsal line is similar to the dorsal, but rather paler, both in the central thread and 
in its lines of grey edging; the second stripe of the ground colour follows; then 
another pale line with dark edges, precisely similar to the sub-dorsal, though rather 
pale ochreous in tint; below this comes a broad stripe of the freckled ground 
colour, marked the strongest along its upper and lower edges, and so little freckled 
along its middle region as sometimes to give a line of the plain ground colour there ; 
the spiracles are along the lower freckled edge, they are whitish-grey, faintly out- 
lined with black; the sub-spiracular stripe is pale ochreous and paler still at its 
edges, the belly and legs being of the same colour but a trifle deeper in tint; the 
tips of the ventral legs are dark brown; the head is brownish-ochreous, brown at 
the mouth and shining, as is also the upper surface of the second segment. Ihave 
distinguished all these markings as well as I could, but in truth, the whole surtace 
