THE BEETLE AND ITS ALLIES 57 



Every part of the plant has its coleopterous enemy. As 

 Le Conte and Horn have said: "As the function of the 

 Cerambycidce is to hold the vegetable world in check by 

 destroying woody fibre, the Bruchidse (weevils) effect a 

 similar result by attacking the seeds, and the Chrysome- 

 lidse by destroying the leaves." 



The list of beetles directly or indirectly useful to man 

 is small. The carrion-beetles, tumble-bugs, and rove- 

 beetles, which feed upon decaying animal and vegetable 

 matter, are useful as scavengers. Of those which serve us 

 by killing other insects injurious to vegetation, the lady- 

 bird beetle stands first. The economic importance to us of 

 this one family can hardly be estimated. Different kinds 

 of ladybirds feed on different species of insects. At one 

 time it seemed that the orange industry, if not that of fruits 

 in general, was doomed in California on account of the 

 destruction wrought by the introduction of a scale-insect. 

 As the insect had been imported, we had no native beetle 

 which attacked it. Search was made abroad, and a lady- 

 bird beetle was found in Australia which feeds on this 

 particular scale-insect. The Australian beetle was intro- 

 duced into California, and now the scale-insect is subdued. 

 The larvae of some of the checkered beetles J feed upon the 

 larvse of boring beetles, while the larvse of tiger-beetles 

 watch at the mouth of their burrows for other insects upon 

 which they feed. Carabid beetles are said to ascend trees 

 in search of canker-worms. Larvae of ground-beetles prey 

 upon the pupating plum Curculios. Other beetles eat cut- 

 worms, and infest the common wasps. 



One beetle, the blister-beetle, known in the markets as 



1 A family of rather small beetles, living in flowers and on trees, and 

 often with contrasting colors. 



