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336 A COURSE ON ZOOLOGY. 



giant black ant prefers a hollow tree or a stump ; the 

 yellow and brown ants raise conical ant-hills of sand 



or earth sometimes 



FIG. 299. a foot high, cham- 



bered and traversed 

 by innumerable gal- 

 leries. Some species 

 of ants reduce others 

 to slavery, compelling 



them to bring food 

 PART OF A GALLERY, WITH ANT WORKING ON , 



TIPTOE, Pogonomyrmex moltfaciens, the and to nurse the 

 agricultural ant of Texas. (From McCook.) larvffi. 



The lepidoptera are 



classified in three families, different in their habits and 

 their forms ; they are the diurnal, generally called but- 

 terflies, the crepuscular, and the nocturnal, the latter 

 two being commonly called moths, 



The diurnal lepidoptera may be recognized by the 

 erect position of their wings when at rest. They fly 

 only during the day ; their colors are usually brilliant ; 

 the chrysalis is usually naked and attached by the pos- 

 terior extremity of its body. There are very many 

 species. 



The crepuscular lepidoptera do not fly all the evening, 

 as their name would indicate ; some are even diurnal in 

 their habits. However, the wings of all are held hori- 

 zontally during repose, and their movements produce a 

 humming sound when flying. The chrysalis is usually 

 enclosed in a cocoon, and attached to a tree or wall or 

 hidden in the earth. Some of the species are very large, 

 one of the South American measuring a foot across the 

 extended wings. The colors are usually sober. The 

 nocturnal lepidoptera fly only at night or at evening 



