56 



ZOOLOGY 



Fig. 60. — Mound and clearing of Harvester ant, near Great Salt Lake, Utah. 



these swarms. Some spiders escajie l)y susjiending themseh'es by 

 their threads, and insects which resemble lea\'es often find safetj' in 

 keeping rigidlj' still. When an ami}' of these ants enters a house, the 



inliabitaiits find it wisest to leave 



\ / 



Fi<;. Cil. — PimpJn perialis, a parasite 

 on the eaterpillar of Clisioeanipa. 

 n. male, /,. female. Photo, by 

 V. H. L. 



the invaders in possession, for in a 

 few hours the house is cleared of 

 every living thing — n^oths, cock- 

 roaches, rats, mice, all have fled 

 or been (hn'oured. 



The leaf-cutting ants arc an- 

 other tropical American species. 

 The colony is ^'cry perfectly organ- 

 ized. The duties of the workers 

 are divided among different gangs. 

 Thus, when a tree has been se- 

 lected, one gang ascends the trunk 



