THE ENTOMOLOGIST. 153 



phenomenon must be quite unknown to them, as they give a 

 full account of the impregnation of caterpillars with foreign 

 eggs. At a 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 

 liave 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 hardls' be detected 

 by the sharpest sight; how uncommonly small the wasp; 



X 



