RfiAUMUR 267 



issue by the same openings. There are, he supposes, a 

 vast number of pores in the skin which allow the air to 

 escape. It is easy with an air-pump, or even with a 

 little strongly heated wax, to prove that the air taken 

 in for respiration is unable to issue at any other points 

 than the spiracles, and it is a little surprising that 

 Reaumur did not think of this or some other decisive 

 experiment. 



The fourth memoir discusses change of skin in a 

 caterpillar. Reaumur was at first in doubt whether the 

 new hairs were enclosed within the old ones or not, and 

 devised the following simple experiment to settle the 

 point. A day or two before the change was due, he 

 cut a number of the long hairs close to the skin, choosing 

 the hairs just behind the head, the hairs of one side of 

 the body, or some other definite group. The caterpillars 

 so treated cast their skins exactly like any others, and 

 the new hairs were found to be entire. Immediately 

 after the skin is cast, Reaumur remarks, the body is 

 damp externally, showing that a liquid had existed 

 between the old and the new skin.^ 



Moths 2 



The external anatomy of moths occupies the fifth 

 memoir. The wings, eyes, antennae, and proboscis 

 receive special attention, and are illustrated by excellent 

 figures. To appreciate the importance of this memoir, 

 we must bear in mind that these things had never been 

 adequately investigated before. Malpighi had dismissed 

 the silk-moth briefly, though he investigated thoroughly 

 the reproductive organs in both sexes. Swammerdam's 

 Biblia Natures (unpublished in 1734) gives a better 



1 A similar liquid facilitates the proooss of moulting in sonio roptiloH. 

 * Vol. I, M^m. V. 



