54 



ANIMALS OF LAND AND SEA 



of the larger dragon flies, especially when other food is scarce, 

 are often very destructive to young fish, and giant water bugs 

 eat small frogs and tadpoles. Generally these predaceous in- 

 sects show slight 

 discrimination in 

 their choice of 

 food, catching al- 

 most anything that 

 comes their way ; 

 but most robber 

 flies when fully 

 grown are curious 

 in having very 

 special preferences. 

 Those stout ones 

 that look like bum- 

 ble-bees eat only 

 bees and wasps, 

 while others catch 

 only butterflies or 

 moths. 



Slow disem- 

 bowelment of the 

 most revolting 

 kind is practiced 

 by the wasps. 

 ti^ilS^^ Most of these, 

 making burrows in 

 the ground, or bor- 

 ing into wood, con- 

 structing cells of 

 mud, or utilizing 

 chinks or burrows which they find, cram them some with 

 spiders, some with large or small flies, or even bees, some with 

 caterpillars, crickets, or other insects, which have been para- 

 lyzed, but not killed, by stinging. An egg is placed in each 



Figs. 15-17. 



The Atka Mackerel, a Snipe-eel, and the 

 Tundra Fish. 



For explanations of the figures see p. xi. 



