14 DKAGOX FI.IES VS. MOSQUITOES. 



sounding sea' inoi-e tlian can possibly be expressed. I 

 certainly agree ^\itll the learned gentlemen of Harvard 

 and Yale with whuni you have communicated, that the 

 subject is at least worthy of careful investigation. I 

 know of no experiments in the propagation of these in- 

 sects. I am plunged over head and ears in my * Amer- 

 ican Spiders and their Spinningwork.' It is the con- 

 sunuuation of fifteen yciirs of labor and observation, and 

 now I am prejiaring hundreds of engravings and colored 

 figures. I can be of little assistance to you, but be as- 

 sured of my cordial sympathy. It is, of course, possible 

 that the experimentation will result in nothing practica- 

 ble; but some of the most heli)ful schemes for the relief 

 of mankind have begun M-itli less promise than this which 

 you propose. IJudoubtedly many failures must be the in- 

 evitable accom})animent of a few successes; and who 

 knows which will be the success and which the fiiilure?" 



Prof. Cope, editor of the " American Xaturalist," whose 

 knowledge of almost every branch of natural history is so 

 exact that his general statements have an unusual value, 

 wrote on the 9th of July : " A prize for a carefully pre- 

 pared practical essay on the means of multiplication of 

 the larger predaceous Libellulidje would be apt to bring 

 out something good." 



Not a little encouragement toward an endeavor to turn 

 additional scientific light upon the question at issue Avas 

 received by finding in a publicati<jn of oue of our highest 

 entomological authorities this statement : — 



" I^ittle, almost nothing, is known regarding the habits 

 of the dragon files, and any one ^vho can spend the neces- 

 sary time and patience in rearing them so as to trace up 



