them from the locality. So complete a removal of the evil does 

 not, indeed, often occur, but most of our injurious insects are kept 

 more or less in check by parasites. Some insects are attacked by 

 three or four, or, it may be, ten or twelve parasites. It is obvious 

 that an investigation of this subject of parasitism is of the highest 

 importance. It is, ot course, a blind and bungling method of war- 

 fare to fight against all insects indiscriminately. We must always 

 remember that there are insects which are of value to the larmer, 

 and the destruction of these is as great a mistake as it is to allow 

 an injurious insect to escape. It is a most fortunate law which 

 seems to prevail throughout the insect world, that vegetable-feed- 

 ing insects, which are mostly injurious, are almost always attacked 

 by one or more, sometimes many, parasites, and as the pernicious 

 species increase, the parasite is very likely to increase, and often 

 the latter' destroys the whole race of the former. 



It is not quite easy, without occupying too great space, to give 

 definite descriptions of these parasitic insects which are our friends ; 

 but the subject is one ol so much importance that, with the aid of 

 the accompanying illustrations, an attempt will be made to give a 

 general idea of some of the more common beneficial insects, 

 although it will not be possii^le to give anything like a complete 

 account of them, or to even mention more than a few. However, 

 the ])rihcipal classes are illustrated. Not only parasitic, but preda- 

 tory- insects, those which aie the lions and tigers of the insect 

 world, going about seeking the bugs they would devour, must be 

 noticed, and it is sincerely hoped that what information is herein 

 given may be of some assistance in enabling the farmer to distin- 

 guish his friends from his foes. The ichneumons, bristle tails, 

 etc., mentioned and figured must serve as types of the groups to 

 which they belong, and, although not strictly correct, yet it will 

 on the whole be safe to consider all similar insects as friends ; for, 

 while some of tiie gall-making insects, as may. be seen in figure 6, 

 numbers 21 and 22, which are of this sort, very closely I'esemble 

 some of the parasitic species, so that they are very likely to be 

 mistaken for them, yet there are not many of them injurious to 

 farm crops, nor likely to be seen about them. For this reason the 

 insects of the sort under consideration which the farmer is most 

 likely to come across, are his friends. Dragon flies devour many 

 small insects, and in all the great groups into whicli entomologists 

 divide the innnense kingdom of the insects, there are some which, 

 l)y destroying their allies, become most valuable friends to man. 



