336 STATE HORTICULTURAL BOClETr. 



remedies could be enumerated by hundreds. Merely to specify a few, we have 

 the popular applications of Paris green, ^London purple, hellebore, and 

 pyretiiruni, in powder or in liquid form; carbolic acid, kerosene and other oils; 

 soft soap and other alkaline washes, lime, ashes, soot, dust, salt, hot water, 

 hand picking, tree-jarring, burning infested twigs, attracting to fires, to lights, 

 or to adhesive sweets — all tending to the destruction of insect life in one or 

 more of its several scages. 



It will readily be conceded that the use of preventives, whenever practicable, 

 is more economical, more effective, and often more convenient than a resort to 

 remedies. An old familiar adage affirms this truth, when it asserts that "An 

 ounce of prevention is better than a pound of cure."' 



He assumed that the deposit of insect eggs could be prevented, giving exam- 

 ples of the use of various odorous substances successfully in accomplishing" 

 this end, and said that the question of how tiie substances employed prevented 

 the egg deposit was a very im})ortant one because upon its answer depended 

 valuable generalization concerning methods of dealing with insect life. He 

 believed insects were guided in the deposit of their eggs by the sense of smell. 

 The marvelous compound eyes of most species had misled people to think that 

 sight was their keenest sense. 



While sharing in this belief I had often wondered at the incomprehensible 

 acuteness shown by an insect in the discovery of the particular species of plant 

 upon which alone the young caterpillars proceeding from its eggs could feed, 

 — in the discovery of a single individual of a rare species occurring in a certain 

 locality, and growing in such a manner as efTectually to hide it from human 

 observation. When its range of food-plants extends beyond a species to all 

 the members of a genus, how could it detect all of the often greatly differing 

 foims ? When a still broader range embraces the several genera of an extended 

 order, a still greater variety of forms are presented, which the rude insect brain 

 must group and classify and claim within its province. How amazing such 

 knowledge without previous instruction. It had no parents living, as in the 

 class of vertebrates, which might teach it by example. It had no ancestors a 

 whit wiser than itself from which to learn. The deposit of the egg in its proper 

 place may have been but the second voluntary act of its imago life, regarding 

 that of flight for the purpose as the first. Perhaps a plant from some distant 

 shore, of which not one of its ever so remote ancestry could have had any 

 knowledge, is brought within its range of wing; its flight is unhesitatingly 

 directed to it, and its precious burden of eggs, without a shadow of mistrust, is 

 at once committed to its leaves. Such knowledge has never been attained by 

 our most distinguished botanists, and it is beyond the scope of human intel- 

 lect. We have called its displays instinct — a word conveniently framed to 

 cover manifestations in other classes of animated beings, which we are utterly 

 unable to explain. As a partial explanation of these wonders it has been sug- 

 gested that to the insect world may have been given senses differing in number 

 and in kind from those which we possess. But all the wonderful jjhenomena 

 attendant upon insect oviposition by selection, is readily explained under the 

 supposition that it is guided and controlled by the sense of smell. 



The essayist gave striking examples of the extraordinary development of the 

 sense of smell in certain animals and in man under peculiar conditions, and 

 asks the question if his theory is not a reasonable one. He then gave the 

 various notions of prominent scientific men as to the location of this sense in 

 iueects. 



