186 POPULAR ENTOMOLOGY. 



through their means thousands of caterpillars are destroyed, 

 which would otherwise do great injury. One species preys 

 on the Aplnda or Plant-Lice, and thus assists in checking 

 the increase of these troublesome little insects. This is the 

 species best known, being often seen in the garden, parti- 

 cularly the male, hovering over the rose-trees, or creeping 

 under the leaves; it is of small size, with long legs; 

 the wings obscurely coloured with bands and spots of black 

 and red. The female pierces the skin of the Aphis, and 

 deposits an egg in the wound, taking great care not to 

 place more than one in each insect; when the grub is 

 hatched, it feeds on the body of the poor victim, and when 

 full grown it spins no cocoon, being adequately protected 

 by the hardened skin of the dead Aphis. In a few days, the 

 now winged insect forces itself from its prison, and flies 

 away to enjoy its brief existence, and add another to the 

 countless myriads of happy beings. Another species is 

 mentioned by Mr. Kirby, as serviceable in keeping down 

 the numbers of the little Midge which attacks wheat when 

 in flower. Having placed a number of the grubs of this 

 mischievous insect on paper, he introduced a female Ichneu- 

 mon amongst them ; she immediately began to pace about, 

 vibrating her antennae very briskly; then fixing on one of the 



