THE INSECTS: HEXAPODA 101 



(Fig. 33) feed upon scale insects and plant lice. Several 

 entire families of Hymenoptera live as parasites on other 

 insects and kill many harmful species. Diseases are not 

 limited to the higher animals. Bacteria and fungi attack 

 and kill some of man's worst insect enemies. 



Insects of the Household. Attention has been called to 

 the unsanitary habits of cockroaches living in houses. 

 Clothes moths, buffalo beetles, and crickets as destroyers 

 of articles of cloth and other organic material (for ex- 

 ample, fur and feathers) have been discussed in earlier chap- 

 ters. These are but the beginnings of the invasion which 

 insects carry against man into his household. The larvae 

 of beetles and of Lepidoptera attack and destroy or render 

 unusable his stored food materials. Cereals become in- 

 fested with webworms, the larva? of minute moths. Beans 

 and nuts are destroyed by larvae of weevils belonging to the 

 Coleoptera. Blowflies lay their eggs on meat that is ex- 

 posed to their attack, and the developing maggots feed 

 thereon. Dr. Britton, state entomologist of Connecticut, 

 in 1917, estimated that it costs the American people two 

 hundred million dollars a year to feed insect pests of stored 

 foods alone. These are but a few of the aggressors against 

 man in his private domain, the home. 



Some insects are even more bold and, if unsanitary con- 

 ditions permit, will attack man himself. Body and head 

 lice and bedbugs feed upon the human body if conditions 

 favorable for them are permitted to exist. In some locali- 

 ties fleas become so abundant as to make life miserable by 

 their bites. Unless houses are kept screened, flies and 

 mosquitoes render man at least uncomfortable and, as ex- 

 plained in the next section, even endanger his life. 



Insects and Disease. Malaria is sometimes said to have 

 been one of the big obstacles to the economic progress of the 

 human race. Sir Ronald Ross, the Englishman who proved 



