224 GENERATION 



passes the urethra. From the root of the penis passes a duct which is 

 strong and thick at the root, but becomes smaller and smaller, and 

 makes a twist or turn upon itself, where it becomes very small. Into 

 this one canal, enter four pairs of ducts ; the first pair are two long small 

 ducts, each of which is coiled upon itself so as to occupy but a small 

 space ; the second pair are larger, and are the common ' vasa deferentia' 

 of each side ; the third pair are two pretty long ducts, nearly as large 

 as the vasa deferentia, that take a slight serpentine course, there being 

 room for them in the abdomen ; and the fourth pair are two small short 

 ducts between the two last. The testes are twelve on each side, [the 

 insect] having twenty-four in the whole ! They are round flattish 

 bodies, each having a duct passing out of its centre like the stalk of a 

 mushroom, which is of some length ; and the whole twelve ducts unite 

 into one, which forms the common vas deferens of that side. I once 

 saw them in copulation, which was exactly similar to [that in] the cock- 

 chafer. 



Moths are a long time in the act of copulation. The large moth is 

 some days. 



Of the Laying of the Eggs of Moths. 



In a middle-sized perfect white moth 1 , about the size of a silk-moth, 

 the female has a great deal of fight brown hair all round the anus. 

 "When she lays her eggs the oviduct is protruded, and when the egg is 

 three-quarters out, she moves the anus from side to side, which brings 

 the protruded egg in contact with the hair, which attaches the hair to 

 the egg so strongly as to pull the hair out by the roots, so that the egg 

 becomes surrounded by them. These hairs, by means of the mucus, 

 stick again to the surface on which the eggs are laid. Putting some of 

 these eggs under a glass shade, in about three weeks they hatched ; and 

 the young worms worked a network all over the inside of the glass. 



In July 1791, I found one of these moths laying its eggs on the leaf 

 of the Paper-tree 2 . I took the moth into the house with a part of the 

 leaf, with some of the eggs on it, with a view to preserve it as a pre- 

 paration 3 . 



Longevity of Insects according to Period of Oviposition. 



I do suspect that the females of insects, respecting longevity, are of 

 two kinds ; one where the female dies the same season in which she is 



1 [The accomplished entomologist, Francis Walker, Esq., believes the species here 

 referred to, to be the ' Brown-tail' moth (Porthisia ckrysorr/ioea).] 



- [Paper Mulberry {Brucea papyri/era).] 



3 [Hunt, Prep. No. 3043. shows the eggs of a Hawk-moth (Smerinthm) attached 

 lo a leaf.] 



