PARASITISM 135 



have been discussed and Lhere being no new items of special interest, 

 we may pass to the consideration of the parasites of adult or mature 

 insects. 



AVhile in the larval and pupal stage the insects are largely unpro- 

 tected and fall easy prey to the designing parasites, thus is not the case 

 with the adult nsects. As a rule the mature insect is much more active 

 and capable of self-protection. In addition to this the hairy covering of the 

 body and the large wings of our moths and butterflies serve as complete 

 protection, £o that none of these are parasitized. In the case of the 

 beetles the body is covered by shields or hard wing-covers which, with 

 few exceptions, serve as efficient armor. The bees, wasps, and flies de- 

 pend to a large extent upon their activity in avoiding their enemies. The 

 grasshooper.s and the true bugs or "stink-bugs" have the tough leathery 

 overlapping f\nich ward off all but a few of the more bold and persistent 

 parasites. In spite of all these difficulties parasitism does occur to some 

 extent during this stage-, ana, although the parasites are few in number, 

 they are scattered through several different groups. 



Among the flies parasitic upon adult insects we have only a few 

 belonging to the Tachinid family which has already been discribed as 

 composed of bristly flies with the bristles on the antennae smooth instead 

 of feathery. The most notable example is the beautiful little fly that 

 is parasitic on our common squash-bug. Some of the Sarcopliagidae or 

 flesh-flies are parasitic upon bettles and grasshoppers. When a grass- 

 hopper starts to fly one or more of these insects dart after it and, if 

 successful, deposit eggs on the unprotected body between the wings. 

 These hatch and the larvae penetrate the body of the host. Although 

 these flies closely resemble both the house-fly and the Tachinids still 

 they may be recognized by the somewhat bristly body, though not so 

 bristly as the Tachinids, a peculiar checkered appearance which is 

 ussually present on the abdomen, and the antennal bristle which is 

 feathered near the base but bare towards the end. 



A Sarcophagid fly parasitic on 

 gTasshopi)ers. 



