BENEFICIAL INSECTS, PREDACEOUS AND PARASITIC 17 



Thus here again are found some " bugs " that are friends and 

 not foes, worthy of all the protection that can be afforded them, 

 and well repaying such careful observation of their habits as may be 

 bestowed upon them. 



Insect Parasites 



Though large numbers of injurious insects are annually de- 

 stroyed by those which are purely predaceous upon them, many 

 more succumb to those minute forms which live parasitically 

 within them. A few of these parasites belong to the order Dip- 

 tera, or true flies, but most of them are classed in the order Hymen- 

 optera, in which order are also included the saw-flies, ants, wasps, 

 and bees. 



Of the half-dozen families of hymenopterous parasites one of 

 the largest and most beneficial is that of the Ichneumon-flies. 

 The illustrations will best show the form and structure of these 

 insects, which the casual 

 observer will hardly be 

 able to distinguish from 

 other families of the group. 

 But it will be noticed that 

 the fine veins of the wings 

 vary considerably in the 

 different parasites figured, 

 and it is by these that the 

 entomologist is enabled 

 to separate the different 



groups and often to iden- FlG - H Maggots of Pimpla inquisitor, a 



parasitic Ichneumon-fly, feeding on a cater- 

 tify the species at a glance. pinar which had spun its cocoon and was 



Both this and the follow- ready of pupate, 

 ing family are peculiar in 



having an exceedingly long ovipositor or egg-tube, of which they 

 make a very good use. It is with this extensile tube that the 

 female deftly punctures the skin of some unsuspecting cater- 

 pillar, and under it inserts her eggs. In a few days there hatch 

 from these a host of young maggots which feed upon the juices and 



