IX. On the reproduction of lost parts in myriapoda and insecta

Abstract The reproduction of parts of the body that have been accidentally lost or removed, is an occurrence of so much interest, in relation to the laws of nutrition and development, that I am induced to trespass on the attention of the Royal Society with an account of some experiments on this subject in the Myriapoda and Insecta. It has long been known to every naturalist that the Crustacea and Arachnida are capable of reproducing their limbs; and it has also been stated that a similar reproduction of parts takes place in some of those insects which are active throughout their whole life, and do not change their form, but merely cast their tegument and increase in size. But it has been questioned whether any reproduction of lost parts can take place in those insects which undergo a complete metamorphosis, and change their form, their food and mode of life in passing from the young to the adult state. No investigations have hitherto been undertaken to decide the question in insects that undergo these changes, nor have any experiments been made to show that a reproduction of lost parts is common also to the whole of the Class Myriapoda. At a meeting of the Entomological Society in November 1839, I exhibited a specimen of Scolopendra sub-spinipes, which had the eleventh leg, on the left side of the body, so much smaller than the corresponding one on the right, although otherwise perfect in regard to the number of its articulations, that I regarded it as a marked instance of reproduction of the limbs in that class. As no experiments had then been made to prove the fact, this opinion was disputed, and the instance pointed out was considered as merely one of an arrest of development. Since then it has been shown as first noticed by Müller, that a reproduction of the legs most certainly takes place in the Phasmidæ; but it is still doubted whether it can occur in the Lepidoptera, and other tribes that undergo a complete change.