No. 4.] THE GYPSY MOTH. 221 



presented by Professor Fernald in an abridged form in Part 

 II of that report. 



It is a distinct advantage in dealing with the moth here to 

 obtain exact information in regard to its habits and capabili- 

 ties for injury in Europe and the means used there for its 

 destruction. We are thereby enabled to compare its habits 

 there and here, see what changes they have undergone and 

 gain some idea of how destructive it is likely to be if allowed 

 to spread over this country. A knowledge of its enemies and 

 their effect upon it will also enable us to judge in some degree 

 as to whether we are likely to find effective natural enemies 

 of the moth in this country. The literature on the ravages 

 of the moths in Europe would seem to indicate that they have 

 not been so serious in southern and central Europe within the 

 last twenty-five years as they were during the century pre- 

 ceding, but that they have been very great in Russia and 

 Siberia within the past fifty years. It appears from these 

 reports that the destruction of vegetation by the gypsy moth 

 in Europe has seldom been as complete as it has been in Mas- 

 sachusetts, though its distribution and ravages have had a far 

 wider range. The excess of injury done here appears to be 

 principally due to its extreme multiplication and to the feeding 

 season being usually much longer here than in Europe. 



The continuous defoliation of trees results in serious injury 

 or death. The destruction of trees by this insect in Europe 

 is only occasionally recorded ; the greatest injury done by the 

 caterpillars to the trees extends over a short portion of the 

 summer ; the trees therefore have an opportunity to refoliate 

 themselves. The damage to fruit interests has often been 

 very great, and whole provinces in Russia have raised little 

 or no fruit in certain seasons on account of the ravages of the 

 gypsy moth. 



Destructiveness of Introduced Insects. 



Even had the gypsy moth never been known as a pest in 

 Europe, it might have become very injurious on its intro- 

 duction here. It is well known to entomologists in this 

 country that our insect pests which are of European origin 

 have become far more injurious here than in Europe. The 

 wheat midge (Diplosis tritici, Kirby.), the cabbage butterfly 



