No. 643] FOOD HABITS OF COLEOPTERA 165 



Summary 



Phytophaga 4,801 



Saprophaga 8,252 



Harpactoph^a 4,985 



i8;5T3 



About 26 per cent, of the species of Coleoptera are phy- 

 tophagous, most of this percentage being made up of the 

 families CurculionidcE, Ceramhycidce and ChrysomelidcB. 

 Almost one half of the species of beetles, or 44 per cent., 

 appears to be saprophagous for the most part and in this 

 group the families StapJiylinidcB, Tenebrionidce and 

 ScarabfEidcB supply over half of the species. In the pre- 

 daceous group, consisting of 27 per cent, of the total, the 

 C'arahida with its 2,165 species is the largest single con- 

 tributor. Thus almost three fourths of the species of 

 beetles in North America are apparently engaged in what 

 we call useful activities. 



