IN MYRIAPODA AND INSECTA. 
289 
instituted a series of experiments on the larvae of the common Nettle Butterfly, 
Vanessa urticce. 
On the 24th of May, in the present summer, I removed with the scissors two of the 
true legs of the caterpillar, on the left side of the body, from each of twelve specimens 
that had not yet passed into their last stage as larvae, but were still in their fourth 
period. These legs were either entirely removed at their base, close to the body, or 
in the tibial or femoral joints. On the following morning I removed the interme- 
diate, or the posterior leg, on the left side, from each of sixteen other specimens which 
had already entered their last larva skin, or fifth period. Six of these were nearly 
full-grown, and would have entered their pupa state in the course of a few days. The 
remaining ten had only recently entered their last skin. The whole of these twenty- 
eight larvae were confined together in a glass vessel, and well supplied with food. 
Some of the specimens seemed to be but little affected by the operation, as they im- 
mediately began to feed very actively ; but on the following morning several of them 
had died from its results. In the whole of those which had the legs removed at the 
base the haemorrhage was at first very considerable ; but in those which had the limb 
removed at the tibial joint it was not so profuse. In the specimens in which the 
limb was removed at the tibio-tarsal joint the haemorrhage soon ceased, but in those 
in which the wound was more serious, it was less readily suppressed. But even the 
individuals that were most injured began to feed with avidity immediately after the 
operation, notwithstanding the excessive haemorrhage that was going on. One of 
these specimens had not only lost the whole of its meso-thoracic leg, but was also 
punctured on the back, and from both wounds the green transparent circulatory fluid 
flowed in large quantity; but the insect still continued to feed very eagerly. In less 
than half an hour I had the satisfaction to find that a coagulation of the effused blood 
was taking place over the wounds, although at each contortion of the body the fluid 
gushed forth afresh. In three quarters of an hour the blood had become somewhat 
more firmly coagulated, and formed a dark black patch, or eschar, over the injured 
parts. In this way, by a coagulation of the effused fluid, the hsemorrhage from wounds 
in insects is first arrested. The rapidity with which this coagulation takes place 
seems to depend greatly on the temperature and comparative dryness of the atmo- 
sphere ; since if the air of the locality in which the insect is confined be loaded with 
moisture, the hsemorrhage continues for a long time, and the individuals often die, as 
was the case with some of my first series. It was in consequence of not being aware 
of this, at the commencement of my experiments, that a greater number of specimens 
died than would otherwise have been lost from the operations. On the fourth day 
only twenty-two were still living; but this great mortality was clearly attributable 
to the cause I have stated. At the expiration of nine days, one of the six larvse that 
were nearly full-grown when the experiments were commenced, changed to a chrysalis. 
At that time only seventeen specimens remained out of the original twenty-eight. 
Those which died were chiefly the youngest ones. By the thirteenth day, June 5th, 
2 p 2 
