chinch-bug, army-worm, corn-worm, leaf-louse, and a host of additional 

 species are on the other. Among the subterranean corn insects we may 

 distinguish a few which feed only on the softened seed in the earth; 

 others confined to the living roots; other root insects which may extend 

 their injuries to the underground part of the stalk; and still others which 

 may also eat the seed. 



While the relations of the injurious species of corn insects to the 

 plant thus differ widely, making it possible to divide the species accord- 

 ing to these relations, groups so formed are by no means as definite and 

 sharply limited as those in a classification based on form and structure, 

 but they overlap and intermingle variously, and may even inidergo 

 radical change with the lapse of time — a change corresponding to a 

 change of habit in a species with the changing conditions around it. 

 This is merely saying in other words that the actions, behavior, habits, 

 and preferences of insects are more flexible and variable and far more 

 readily adaptable than such of their structures as are used in their 

 classification. 



Adaptations and Reactions of the Corn Plant to its 



Insect Visitants. 



There is little in the structure or the life history of the corn plant to 

 suggest any special adaptation to its insect visitants — no lure to insects 

 capable of service to it, or special apparatus of defense against those 

 especially liable to injure it. The fertilization of its seed is fully pro- 

 vided for without reference to the agency of insects, and would be as 

 well accomplished if none of them ever carried ])ollen from the tassel of 

 one plant to the silk of anotlicr. Hence the i)lant secretes no honey 

 and has no floral odor or colored bloom. It has no armature of spines 

 or bristly hairs to embarrass the movements of insects over its surface 

 or to defend against their attack the softer and more succulent foliage at 

 its growing tip. It secretes no viscid fluids to entangle them, and forms 

 no chemical poisons or distasteful compounds in its tissues to destroy or 

 repel them. The cuticle of its leaf is neither hardened nor thickened by 

 special deposits; its anthers are neither protected nor concealed; and its 

 delicate styles — the silks at the tip of the ear — are as fully exposed as if 

 they were tlie least essential of its organs. Minute sucking insects are 

 able at all times to pierce its roots and its leaves with their flexible beaks, 

 and with the single exception of its fruit there is no part of it which is 

 not freely accessible at any time to any hungry enemy. Only the kernel, 

 which was lightly covered in the wild corn plant by a single chaffy scale 

 or glume, has become, in the long course of development, securely inclosed 

 beneath a thick coat of husks, impenetrable by nearly all insects; and 

 we may perhaps reasonably infer that among the possible injuries against 



