xxxvi 



THE GYPSY MOTH. 



Report of Prof. John B. Smith, D.Sc, of Rutgers College, 

 State Entomologist of New Jersey. 



New Brunswick, N. J., June 20, 1893. 



Dear Dr. Fernald : — Since my return to New Brunswick I have 

 been thinking over what I saw of the work of the gypsy moth 

 committee near Maiden, Lynn and Swampscott, and with the 

 lapse of time my admiration for the work accomplished has in- 

 creased rather than diminished. When I received your invitation 

 I was, I think I can truly say, free from actual prejudice, yet with 

 a disposition to believe that the work of the committee was 

 palliative merely, and that actual extermination was impossible, an 

 impression to which I had given public expression. I am pleased 

 to say that I have seen ample evidence to induce a change of 

 opinion, and my belief is now that if the committee is as well 

 supported as it deserves to be it will accomplish the end for which 

 it was created. With this expression of my present belief, you 

 will understand that my suggestions are not in the nature of 

 adverse criticism. 



First, concerning the experiments in progress at Amherst, at 

 the present time. These consist of a test of the action of certain 

 insecticides on larvae of all ages, and in contemplation are experi- 

 ments concerning possible parthenogenesis, fixing the relative time 

 of issuing of the sexes from one batch of eggs and the effect upon 

 the fertility of the eggs of close breeding, — that is, between 

 males and females bred from the same egg-mass. 



All these experiments are not only of the highest scientific 

 interest, but also of the utmost practical importance. 



If parthenogenesis is possible, the danger of spreading the 

 insects by carrying off single specimens is vastly increased, and the 

 most stringent measures to prevent such distribution are justified. 

 While parthenogenesis in the Lepidoptera is extremely rare, yet 

 cases have been recorded in the same natural group to which this 

 insect belongs, and the inquiry is therefore by no means a merely 

 curious one. 



Fixing the relative time of the emergence of the sexes of the 

 same brood is of very great importance, for, if males and females 

 issue at such intervals as to make it unlikely that they can pair, 

 the danger from the distribution of even several larvae from the 

 same batch of eggs is materially lessened. 



The determination of the effect of in-breeding is equally im- 

 portant, for much the same reason. 



Finally, the experiments with insecticides are of peculiar interest, 



