COLEOPTERA 115 



most abundant in June and July, consume great num- 

 bers of plant lice. In some places in. California the de- 

 structive orange scale has been entirely kept in check 

 by a species of ladybird beetle, and lately 

 the Asiatic ladybird imported from China 

 is proving a great destroyer of the San 

 Jose scale. The beetles pass the winter 

 in the adult state, often coming into 

 houses, where they should be protected. Fm Larva 

 The Leaf-eating Beetles, numbering ten of ladybird bee- 



,, -. ... , tie twice natu- 



thousand species, are injurious to garden raisize. 

 vegetables and many shade trees. The 

 best known of these are the Colorado potato beetle, the 

 asparagus beetle, and the elm leaf beetle, whose depredations 

 cost millions of dollars annually. The Colorado potato 

 beetle dwelt near the base of the Rocky Mountains until 

 1859 when it began to be a pest in the potato fields of the 

 western settlers. Having acquired the habit of feeding 

 upon the potato, it spread rapidly, reaching the Atlantic 

 coast in 1874. The pest is easily kept in check by spray- 

 ing the potatoes with Paris green and water or sprinkling 

 them with fifteen parts of flour to one part of Paris green. 

 The Coleoptera exhibit a complete metamorphosis, but 

 the forms and habits of the larvae vary widely. Some dwell 

 underground, some thrive on decaying wood, and some 

 prey on other insects. With the exception of the lady- 

 birds, and carrion beetles whose larvae feed on decaying 

 flesh, the members of this order are mostly injurious. 

 Instead of taking food by sucking, as is the habit of all the 

 bugs, they chew their food and are therefore readily killed 

 by spraying the vegetation with poisons. 



