71 



In Europe, besides the articles of Giard, I have noted in my imperfect 

 reading only an unsuccessful experiment with a parasitic lungus of the 

 migratory locust, reported as Lachnidium acridiorum. 



I must not leave this subject without more special reference to the 

 remarkably extensive, suggestive, and thoroughly conscientious work 

 of Prof. Snow on the propagation and dissemination of the diseases of 

 the chinch bug, set f-rth with considerable detail in his report already 

 referred to. Excepting the war on the gypsy moth in ]\Iassachusetts, 

 it is the largest practical undertaking of the year in economic ento- 

 mology. 



Certainly this whole interesting and, as I believe, really promising sub- 

 ject has now been so far opened up that neither entomologists nor botan- 

 ists will be willing to set it aside until it has been thoroughly and criti- 

 cally investigated. It is a very extensive subject when one thinks of 

 the number of fungous species capable of killing insects, of the number 

 of insect species subject to their attack, and of the limited natural dis- 

 ti'ibution of many of the fungous forms, and when one learns — as he 

 will shortly by experience — the numerous and various conditions which 

 will aft'ect both laboratory experiments and field applications. I need 

 not say that the whole matter is involved in diflQculties such as make 

 absolutely necessary the strictest methods of experimental science. 

 Without these we should presently find ourselves swamped by a mass 

 of errors or dubious results which could best be disposed of by leaving 

 them on one side as hindrances rather than helps to progress. 



We ought also carefully to guard the agricultural public against the 

 disposition of a certain number always to run after any new thing, es- 

 pecially if it has a sensational character. The credit of an unfinished 

 investigation may easily be completely broken down in advance by a 

 too eager ai)proj)riation of unverified results. The idea of starting a 

 flame of insect disease in one corner of an infested field to run speedily 

 over the ground, destroying the insect enemies of the crop with no in- 

 jury to the crop itself, is so attractive to the credulous or to the espe- 

 cially enterprising farmer that he is likely to trust the safety of his crop 

 prematurely to this method to the neglect of other more certain, but 

 more expensive measures ; and if a failure follows, whatever the causes 

 or the circumstances, the reaction will be likely to strike too hard and 

 often in the wrong place. 



The kindred and really much less difficult subject of the insect para- 

 sites of insects has received practical attention in this country, so far 

 as I have seen, only from the agents of the U. S. Department of Agri- 

 culture. Mr. Koebele's repeated journeys to Australia in behalf of the 

 orange-grower have attracted general attention. They have resulted 

 in additional importations, more or less successful, to this country of a 

 new Vedalia feeding on Icerya purchasi ; of two species of Coccinellid* 

 (belonging to the genus Orcus), enemies of the red scale and other Coc- 

 cidiTi; of a number of Scymnids; of a Coccinellid devouring Dactylo- 



