74 FIRST ANNUAL REPORT OF THE STATE ENTOMOLOGIST. 



trolled by this sense, for example, most of those which in their larval 

 stage live in the water and are predaceous upon other animal life, as 

 many of the Neuroptera and some of the Coleoi:)tera, The purpose of 

 oviposition in such is accomplished if the eggs are deposited convenient 

 to water. Then there are Hymenoptera, as bees and wasps, which 

 place their eggs in cells constructed by them, having previously pro- 

 vided for the grubs to be hatched, their needed food ; and Orthoptera, 

 that only require for their eggs secure deposit in the ground. Excep- 

 tions to the rule need not be multiplied, for they will readily present 

 themselves. 



And now, to proceed without further delay to the application which 

 it is proposed to make of the views above presented, of the par- 

 ticular sense, which, in many insects, controls their oviposition. If 

 the insect discovers the plant upon which its larvse feed, and is drawn 

 to it for the deposit of its eggs by the peculiar odor characterizing and 

 emanating from it, then, if that odor be neutralized or overpowered 

 by the introduction of another stronger odor — a counterodorant, it 

 might be termed — eggs will not be deposited upon the plant ; it will 

 be preserved from such attack as effectually as if it were inclosed in 

 glass. 



We already know several substances, some of which have been 

 named, which are sufficiently powerful to overcome many vegetable 

 odors. It is not necessary that they should be disagreeable or repul- 

 sive to the insect. We need not, therefore, search for substances dis- 

 agreeable to us, which might prove quite otherwise to insects. We 

 do not know that camphor, carbolic acid, or naphthaline, when in- 

 closed in our insect cabinets, preserves them from the entrance of the 

 Anthrenus and Dermestes, by being disagreeable or repellant to them, 

 but we do know that their strong odor is suflficient to overpower that 

 of the dried insects, so that the posts may not be attracted for the de- 

 posit of their eggs. We have doubtless erred in assuming that certain 

 odors are disagreeable to insects, and that for this reason their pres- 

 ence protects from insect attack. That some odors are not attractive 

 to them is probably true, and in this truth may lie the explana- 

 tion why certain individuals enjoy immunity from the attack of 

 mosquitoes, bed-bugs and fleas in infested localities. The protection 

 afforded to visitors of our northern wilderness from the black-fly and 

 the mosquito, through pennyroyal, oil of tar, and carbolic ointments, 

 results, doubtless, from their overpowering the odor proceeding from 

 the exposed portions of the body ; and, in the same way, the creosotic 

 odor of the smudge-fire smoke prevents the attack of the midge. 



The chief requisites in the materials to be employed for plant pro- 

 tection, in the manner proposed, are strength and permanency ; the lat- 



