178 
[ January, 
cise of such a choice seems to fit in better with larval instincts than 
with those of the perfect state ; and, moreover, there was certainly, in 
one instance, a marked difference in the sizes of two larvae feeding 
together. — J ohx H. Wood. 
Tarrington, Ledbury : 
22 nd November, 1880. 
On September 23rd, 1S79, Dr. Wood kindly sent me two larvae of 
Pempelia hostilis, each between two leaves of Populus tremula , spun 
together with silk, to which quantities of frass were adhering. 
One larva was full grown, the other quite small and preparing to 
moult, three-eighths of an inch in length and very slender, with 
blackish head and collar plates, light pinkish-drab body with dorsal 
stripe just a tint darker, and having on either side of the back two 
cream-coloured lines, and along the spiracular region two paler cream- 
coloured stripes, the lowest slanting downwards just at the end of 
each segment throughout its course, the ground colour between these 
and also of the belly paler than that of the back and sides : after 
moulting on the 26th, it assumed the colour of the full grown example, 
though it refused to feed, and in course of a day or two a parasitic 
larva ate its way out, which proved fatal to the unlucky victim, whose 
shrivelled-up skin alone remained. 
The full grown larva measures nearly three-quarters of an inch 
in length, of moderate slenderness, the head broad and full, about as 
wide as the second segment, the body tapering behind from the tenth 
to the end of the thirteenth, the thoracic segments deeply wrinkled, 
the others with a deep transverse wrinkle a little beyond the middle, 
the ventral and anal legs short and much beneath the body ; the 
rather shining head is blackish-brown, having a broad oclireous stripe 
on the crown of each lobe and a streak above the mouth, papillae black, 
finely ringed with white ; the ground colour of the body is a dingy 
blackish-olivaceous-brown, darkest on the anal flap, rather glistening 
on the second segment, but quite dull on the rest of the body, two 
fine black lines on the collar change from thence to a plain dorsal 
stripe, rather darker than the ground colour as far as the last segment, 
where it is black ; continuous from either lobe of the head is a broad 
sub-dorsal ochreous stripe on the second segment, opening out beyond 
in two lines which, after passing the thoracic segments, become more 
dingy and somewhat grcyish-ochreous, and show but faintly ; midway 
along the side occurs the faintest possible trace of an extra line, thin 
and indistinct, a sub-spiracular stripe begins on the third segment and 
