THE ENTOMOLOGIST. 153 
phenomenon must be quite unknown to them, as they give a 
full account of the impregnation of caterpillars with foreign 
eggs. Ata time when we knew nothing about the impregna- 
tion of insects’ eggs, we found some eggs of the fir-tree 
arrow-tail moth, which were blackish or iron-coloured, and 
these first caused us to suspect that something strange must 
have happened to them, for we well knew that the arrow-tail 
eggs had not this colour, either when empty or when full: 
therefore we looked at them very narrowly, and, behold, we 
discovered in each egg an uncommonly small hole, out of 
which it was impossible for a caterpillar to have crept. But 
what then? Without doubt, nothing else but one or more 
of the very smallest wasps. However, this was simply a 
guess; but the same day we were convinced of the truth of 
the matter, for shortly after we found one of these eggs, out 
of which apparently the caterpillar had come, and which 
was an empty shell, as clear and white as glass, the hole or 
opening therein being proportionately wide to the size of the 
caterpillar, which had made its escape through it. This 
strengthened not a little our guess; but what settled the 
matter was this, namely, we discovered on a fir-spine seven 
small eggs of the moth, whose caterpillar is called the 
jumping-caterpillar (“spring-rups”). They are as big as the 
smallest pins’-heads, or so-called gnat feet: these eggs were 
likewise iron-coloured, and, looking very closely at them, we 
saw also in them a right small hole, out of which no cater- 
pillar could have come; immediately afterwards we found a 
small shoal of these eggs on an oak-leaf, having the same 
quality ; but luckily there were some of them which had not 
yet any hole in them. These we kept, when we got home, in 
a glass well pasted up at the top; and, behold, in two days 
the wasps actually came out of them, uncommonly small, 
yellow in colour, with round shining wings. The affair was 
settled; and the fact was proved, by this discovery, that the. 
eggs of insects are impregnated with the seed or with the 
eggs of other insects, and thereby destroyed. 
§ 6.—Just consider how small an egg must be which is of 
the size of the very smallest pin’s-head; how, beyond 
measure, small the little hole therein, out of which the little 
wasp has crept,—so very small, that it can hardly be detected 
by the sharpest sight; how uncommonly small the wasp; 
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