116 Objects for the Microscope. 



a hole is pierced and the egg laid just where it ought to be. 

 The great and unaccountable marvel is, how it knows whe- 

 ther the larva has been touched before or not. But so it 

 is, and thus it avenges us of our tiny enemy. 



MICROGASTER GLOMERATUS. 



These you will always find mounted at Baker's, Smith and 

 Beck's, and Ladd's. They are exquisite little creatures and 

 some of our best friends. Observe its large eyes, its beau- 

 tiful antennae, the last joint sculptured so delicately that it 

 can only be well seen with a J-inch lens. The ovipositor 

 is partly drawn out, and if the insect is well prepared, you 

 may see the mechanism by which it acts, two powerful 

 elastic springs, braced across by three loops or tendons on 

 each side, which keep the instrument in place during its 

 rapid action. This fly is metallic green and gold ; the wings 

 have but two cubital cells, and, owing to their want of 

 nerves, can seldom be properly displayed. So they should 

 be examined on the unprepared insect, which is abundant 

 on our windows and in our gardens. 



The first time I saw the transformation of this Ichneumon 

 was a great surprise, a child's wonder never forgotten. 

 I had kept some Cabbage Caterpillars in a box, feeding 

 them duly, and expecting the white butterflies whose pretty 

 eggs I had read of and longed to see ; when, one day as I 

 was considering my largest caterpillar, now full-grown and 

 ceasing to eat, instead of commencing as usual to prepare 

 itself for transformation, I saw in one moment that it was 

 dying, and a host of tiny worms suddenly pierced from its 

 inside in all directions, wriggled out, and began to spin 

 so fast that in about ten minutes nothing could I see but a 

 heap of small yellow silk cocoons, and the skin only of my 

 poor fat caterpillar. What it meant I could not tell, nor 

 had I then read the account of it in Kirby and Spence ; 

 but I took the cocoons, put them in a glass covered with 

 muslin, and in about a fortnight from that time the cocoons 

 were pierced and empty, and twenty of these pretty green 

 and gold flies were out. I learnt their name afterwards, 



