186 POPULAR ENTOMOLOGY. 



through their means thousands of caterpillars are destroyed, 

 which would otherwise do great injury. One species preys 

 on the ApliidaS) 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, 

 particularly 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 Ich- 

 neumon amongst them ; she immediately began to pace about, 

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



