252 fApril, 
It seemed that on reaching the centre of the stem they proceeded downwards, 
at first giving no sign of their presence ; but at the end of a month — about May 
23rd — they had reached the bottom of the stems and the crown of the roots, and 
several of the plants began to show signs of decay. On the 4th of June one larva 
was extracted from near the bottom of a stem, and by that time measured about 
five-eighths of an inch. Being placed on another plant it made itself at home there 
also, and fed and grew till July 10th, when it was again examined, and being found 
then to measure one inch and three-eighths, was sent to me to be figured. 
It appeared very uncomfortable when taken out of its food-stem and exposed 
to light while being depicted, and when replaced on the stem soon found its hole 
and disappeared within. 
I attempted to rear it on a cut stem of Heracleum inserted in a pot of moist 
earth, but after a few days it left the stem and died in a very flaccid condition. 
Meanwhile the larvae which had been undisturbed seem to have eaten away and 
grown more rapidly, penetrating even into the main root of the plants, and causing 
them to wither. By July 10th Mr. Doubleday examined one larva which was 
nearly full-grown, and about this time probably most of them became restless and 
wandered off in search of fresh food, for about the 18th of the month neither Mr. 
Hellins nor I could find one left in any of our plants, and Mr. Doubleday had 
but few remaining. 
However, on the 19th he most kindly sent me a large root with two larvEe, then 
about one inch and five-eighths long, and on the 25th another — a fine fellow, two 
inches long, and apparently full-fed. 
Before describing the larva I may here at once say that neither of us succeeded 
in rearing an imago ; those larvae that did not run away became infested with 
parasites {Microg aster alvea/rius), and thus perished miserably. 
However, M. de Graslin (to whom Mr. Doubleday had sent eggs) was mora 
fortunate in France, and succeeded in rearing several fine moths. 
The shape of the larva (after it has attained some size) is moderately stout, 
cylindrical, tapering but little at either extremity, smooth and shining; the folds 
and segmental divisions very slightly indented, a triangular inflation round the 
spiracles ; the tubercular warty spots slightly raised and shining, and all the leg3 
well developed. 
In colour the half-grown larva is of a dull flesh tint, tinged with green beneath 
and at the segmental divisions, but much suffused with a deep dull pink on the back ; 
the warty spots blackish. Wlien two-thirds grown, it is wholly of a deep but dull 
flesh colour, slightly suffused on the anterior segments with a dull red. 
The full-grown larva is flesh colour, having the dorsal pulsating vessel visible 
as a stripe of a darker tint of the same. The head is, as in the other stages of 
growth, brownish-red, and the mouth dark brown. The reddish shining plate on 
the back of the second segment is divided down the centre by a thin line of flesh- 
colour, and is thickly margined in front (where it is widest), and more delicately 
behind, with dark brown. On the anal segment there are four brownish-red 
plates, thus placed : on the anterior part above the fold of the anal flap a central 
semi-circular plate margined with dark brown, and on each side of it at an obtuse 
angle a small narrow oblong plate ; the fourth and largest plate is on the anal 
flap, and has its anterior edge undulating, and margined with dark brown, its anal 
