326 



ALIST [Vol. LIV 



torium; stumps of oaks cut the previous year; and oak- 

 galls. Notwithstanding such diversity within the family, 

 the individual species are nearly monophagous, or oligo- 

 phagous on related plants. Such a condition would seem 

 to have arisen through sudden mutations in instinct 

 rather than from numerous smaller variations having a 

 selective value, for in the latter case we should find poly- 

 phagous forms developing in sonic places at least. 



Another, much smaller family of rather generalized 

 structure, the wood-boring Cossidae, have habits similar 

 to many of the Sesiidse, but their selection of food-plants 

 is very different. Typically they are oligophagous, but 

 some species, including the well-known and destructive 

 shade-tree pest known as the leopard-moth (Zeuzera 

 pyrina) introduced from Europe into the eastern United 

 States, has been bred in this country from an almost end- 

 less variety of shrubs and trees, as it has been in Europe 

 also. As listed by Chapman, the American food-plants 

 belong to twenty-two families of plants and to nearly 

 fifty genera. Almost all that can be said of the leopard- 

 moth's bill-of-fare is that it includes no conifers. 



Cossus lifinipcrda, another Kuropean species is si rongly 

 polyphagous, but many of the exotic species appear to 

 avail themselves of a rather restricted diet. As this lat- 

 ter is perhaps due to lack of knowledge, it may be unwise 

 to draw any conclusions at present. 



In other families of moths the same phenomenon is fre- 

 quently encountered. The large group of Noctuidae, com- 

 prising the owlet-moths, feed mainly upon the foliage of 

 a wide rang of plants, while the list of food-plants for 

 the numerous species varies greatly in extent. To at- 

 tempt to classify the food-habits of this group would re- 

 quire much time and space, but it may be said that there 

 are species in certain genera, as, for example, the cotton 



