INSECTA 87 



There are many arthropods which use grasshoppers for 

 food (Fig. 42). The large orb- weaving spiders spread their 

 snares in the low vegetation. Small mites lurk beneath 

 leaves, waiting to attach themselves to some unwary 

 grasshopper and suck his blood. Fierce robber-flies dart 

 over the fields ; ever ready to pounce down and carry a 

 grasshopper to some retreat to be devoured at leisure. The 

 wasps and beetles are also important enemies among the 

 insects. Some wasps store their nests with nothing but 

 grasshoppers. 



All the enemies mentioned up to this time seek to devour 

 the grasshopper, piecemeal or in toto. We have now to con- 

 sider certain animals which invade the interior of the body 

 and live as parasites. 



Often on a hot day you may see a lazy grasshopper flap 

 slowly along, changing his feeding ground. In the midst of 

 his course he is pursued and touched for an instant by a 

 swift little fly, which then goes about its business. This is 

 a tachina-fly, and it needs only a fraction of a second to 

 poke an egg between the segments of the grasshopper's 

 abdomen. The egg hatches into a maggot which straight- 

 way begins to bore his way into and through the interior 

 of the grasshopper, feeding as it goes. The vital organs 

 are left until the last, so the grasshopper drags out a miser- 

 able existence as a living hotel for this voracious larva. 

 Some flesh-flies also lay their eggs in grasshoppers when they 

 have a chance. Certain of the horsehair worms likewise 

 live for a part of their life cycles in these abundant insects. 



The grasshopper, like man, is subject to certain diseases 

 which make it sick or even cause death. These are, in 

 addition to the large parasites already mentioned, mostly 

 caused by bacteria and parasitic fungi. Such pathogenic 

 organisms are more abundant, and hence more easily 

 acquired, during damp weather. Wet seasons are, there- 

 fore, undesirable for the grasshopper but good for the 

 farmer. Parasitic plants, such as bacteria, are able to 

 enter the body more readily if there is a wound on the 



