THE SELECTION OF FOOD-PLANTS BY INSECTS, 

 WITH SPECIAL REFERENCE TO LEPI- 

 DOPTEROUS LARViE 1 



DR. CHARLES T. BRUES 



The instinctive behavior exhibited by phytophagous 

 insects in the selection of their food-plants is always a 

 matter of interest to entomologists, and it is one of the 

 fundamental principles underlying' the application of en- 

 tomology to agriculture, horticulture and forestry. 

 Nearly all insects show a great fixity of instinct in this 

 respect, but a most cursory examination of the habits of 

 almost any group will reveal a considerable variation 

 among different species, particularly with reference to 

 the number of plants regularly utilized as food and in 

 the selection of closely related or of very diverse plants. 



The origin and development of the association between 

 insect species and plant host has been the basis for a 

 considerable amount of speculation which has increased 

 in proportion to the additional knowledge cuntinn.-illy 

 added through field observation, collection, and rearing 

 of insects. 



Before considering any of the theories advanced to ac- 

 count for the association of insects with definite plants. 1 

 shall attempt to give a very brief account of the salient 

 facts concerning food-plants which appear to be suffi- 

 ciently definite for orderly arrangement, restricting the 

 discussion for the present, mainly to one of the better 

 known orders of insects. 



The term phytophagous with reference to insects is 

 commonly employed in a considerably restricted and 

 rather inaccurate sense, including only those species that 

 feed nnon the liiVher nlnnts. meanimr bv tln-se tie' tVrns 



