348 GENERAL BIOLOGY 



periodically. Of course, it takes time for the new skeleton to harden, 

 so that immediately after shedding its covering the animal is rather soft. 

 The wings appear after the first moult (Fig. 227). They increase in 

 size with each moult but become functional only after the final moult. 

 An insect which at birth resembles its parent, but is not entirely like it, 

 as the young grasshopper, is called a nymph ( ). 



The last moult takes place in the late summer. The nymph then 

 "climbs up some grass stem or similar object, and, taking firm hold, 

 often with its head pointing downward, remains motionless for several 

 hours, till the skin swells over the head and thorax and finally splits 

 open along a median dorsal line. From this old skin the new head, 

 thorax, legs, wings and abdomen are slowly withdrawn while soft, ex- 

 panding and hardening within half to three-quarters of an hour." 



It is then a full-fledged adult and is called imago. After the eggs 

 have been laid in the fall most of the locusts die. 



BEHAVIOR 



As there are more different species of insects than there are of all 

 other animals together, it is not strange that insects should be of con- 

 siderable interest and importance. 



They illustrate better than any other type of animal the interrela- 

 tionships and interdependence of all living things. 



Pollen is carried from one plant to another by insects (Fig. 239), 

 thus permitting vegetation to grow wherever there is sufficient heat 

 and moisture. This makes food more plentiful. Injurious animals and 

 pests are kept down even among their own kind. For example, the swift 

 little tachina fly (Fig. 240) pokes its egg between the segments of the 

 grasshopper's abdomen, which egg then develops into a maggot, and 

 this maggot bores its way into the interior of its host, feeding on the 

 living substance as it goes. It leaves the vital organs until last, so that 

 the grasshopper does not die until the maggot has abundantly supplied 

 itself with nourishment. Then, too, insects furnish the most abundant 

 food for birds, worms, toads, fish, and other animals. Even man has 

 not hesitated to use them as food. The Bible speaks of John in the 

 desert feeding on locusts and wild honey; one itself, the insect, the other, 

 the product of an insect. 



In the markets of Manila large piles of grasshoppers with their 

 appendages removed are offered for sale, ready for cooking. The Moors 

 fry locusts in butter and they are said to make a very palatable dish. 

 In fact, many of the Indian tribes have been known to use not only 

 grasshoppers, but ants as well, as a part of their diet, while the natives 

 of Uganda keep crickets in a warm oven for their musical sounds. In 

 China it is said that fights are staged between crickets and that this is 

 a favorite method of gambling. 



The larvae or grub of the warble fly is eaten by the Dog Rib In- 



