No. 633] FOOD-PLANTS AND INSECTS 



825 



regions, while those of other species are so loose that 

 they restrict their owners only to a comparatively very 

 small extent. Such conditions certainly point to instinct 

 as the determining cause of food selection, rather than 

 physiological adaptation to specific kinds of plants. 



In connection with cosmopolitan butterflies, Scudder 

 noted many years ago, that there are no species of re- 

 markable distribution known to feed upon Leguminosas 

 or grasses, although these plants are cosmopolitan and 

 harbor many species. I am inclined to believe, however, 

 that this has no significance, particularly in view of the 

 aforementioned Coliads that feed upon Cassia in various 

 parts of the world. * 



Many other groups of Lepidoptera conform quite 

 closely in food-habits to the butterflies, although some 

 show greater diversity, especially in affecting different 

 parts of the plant, and it may be said in general that the 

 larger moths are less apt to be monophagous than the 

 butterflies. 



Among the hawk-moths or sphinx-caterpillars several 

 Hil>i';miilics show a restriction to groups of related plants, 

 while others do not. Thus in this cosmopolitan family, 

 one subfamily (Oluvrocampinae) feeds on Vitaceae, with 

 an admixture of diverse other plants, another (Macro- 

 glossime) on Caprifoliaceae exclusively, another (Sphin- 

 gineae) to a great extent on Oleaceae together with other 

 plants as different as Conifers, Solanacea?, Euphorbiaceae 

 and Labiatae, while one (Smerinthinae) exhibits no appar- 

 ent preference. 



The family, Aegeriidae, or clear-winged moths, live in 

 the larval stage in the interior of plants, tunneling 

 through the tissue. They affect a very wide series of 

 plants, herbs, shrubs and trees, as can be seen from 

 the following abbreviated list which represents the range 

 in habits of some of our eastern North American repre- 

 sentatives; stems of Cucurbits, Vernonia, blackberries, 

 currant, grape; wood of pine, willow, lilac, maple, oak, 

 peach; roots of Clematis, persimmon, blackberry, Eupa- 



