INSECTS IN RELATION TO HUMAN WEALTH 563 



Weevils, several species of small beetles with beaks, are all 

 very destructive to stored grains, beans, peas, etc. Infested 

 granaries and warehouses need to be thoroughly fumigated with 

 carbon disulfid, which kills the eggs and the larvae as well as the 

 adults. The cotton weevil is a very serious pest (see Fig. 231). 



Flour is often spoiled by 

 other beetles, as the meal- 

 worm (the larva of a black 

 beetle, Tenebrio (Fig. 232)), 

 and by a species of moth, E/?/f- 

 estia kiiehniella (Fig. 233). 



The larva of the so-called 

 buffalo moth, or carpet beetle, 

 is very destructive to rugs 

 and other woolen material 

 (Fig. 234). 



406. Insects and useful 

 plants. Since men first culti- 

 vated plants for their own 

 use, insects of one kind or 

 another have caused parts of 

 each year's work to be wasted. 

 There are early records of 

 the destruction caused by lo- 

 custs, and this name has come 

 to be applied to many varie- 

 ties of insects that move in 

 hordes. One of the plagues 



of Egypt was a swarm of locusts— insects which are repeatedly 

 referred to in the Bible, and which still do much damage. 



For fifty years the Federal government and the various states 

 have kept up systematic work through experiment stations and 

 special agents and commissions, designed to counteract the in- 

 juries done to valuable plants by insects. It is estimated that 

 the damage done to our crops by the activities of insects 

 amounts to from six hundred million to eisfht hundred million 



Fig. 230. Destruction by ants 



Part of a post completely ruined by the 

 excavations of carpenter ants. There are 

 several species oiCamponotus and of other 

 genera which are known to bore into wood. 

 (From photograph by New York Botan- 

 ical Garden) 



