182 Forty-seventh Report on the State Museum 



How a work of such magnitude — extending over two hundred 

 square miles, with the insect so abundant that in one locality the 

 entire side of a house was so closely covered with the caterpillars 

 that the point of a pencil could not be thrust among them with- 

 out touching them — could have been accomplished, was an 

 enigma to me until the means by which it was done had been 

 shown and explained to me. 



The only suggestions that occurred to me to offer to the com- 

 mittee in response to their request, were these two: Now that 

 the mechanical details of field-work were rapidly diminishing 

 with the steady reduction of the insect, there was both the 

 greater need and the opportunity of such scientific work as might 

 serve to complete the labors of the committee and present the 

 result in form that would render it available for future use when- 

 ever the necessity might arise for a resort to similar methods in 

 other insect invasions hereafter. A volume or two, which should 

 treat exhaustively of the gypsy moth and the niethods employed 

 for its extermination, might be another contribution to natural 

 science which would rank with those which Massachusetts had 

 already made. 



It was also recommended that at this stage of the committee's 

 work, the cultivation of the parasites of the gypsy-moth (of which 

 about a score of native ones are already known) be entered upon 

 and conducted with all the knowledge and skill that could be 

 brought to bear upon it. 



A plan for the artificial rearing proposed was suggested, 

 embracing in brief these points: The entire collection of the 

 pupae for this year, which might amount to twenty thousand, should 

 be preserved, placed in suitable cases, and kept, through cold 

 storage, from giving out their parasites until caterpillars of suit- 

 able age and reared from eggs gathered for the purpose, could be 

 inclosed with them to receive the entire parasitic oviposition. 

 The parasitized caterpillars should be properly guarded until 

 their pupation, when the parasites that they would disclose within 

 the cases should have a caterpillar supply in readiness for them. 

 This round could be repeated as long as there seemed to be the 

 necessity for it and the parasites could be obtained. 



By the above method, or by some modification of it, it would 

 seem that an actual extermination of the insect can be effected, 

 and possibly in no other way. 



