48 



BULLETIN 1103, U. S. DEPARTMENT OF AGRICULTURE. 



sect at present. This may have a considerable influence in lessening 

 the ravages of this species. 



Two of the introduced enemies of the gipsy moth are vigorously 

 attacking this host, namely. Cortipsifaira conoivtmata Meig. and 

 Calosoma sycophant a L. These two enemies are undoubtedly re- 

 sponsible for the checking of the damage done by the satin moth. 

 Three native tachinid flies are also commonly bred from the larvae of 

 the species — Tachina mella Walk., Euphorocera cldripenms Macq., 

 and WintTvemia quadripustulata Fab. Telenomm ralifornicus Ashm. 

 has been reared' from the eggs. 



The solid area on the map (Fig. 26) indicates the region infested 

 in 1920. while the uncolored named towns are the additional ones 

 infested during 1921. 



Table 11 gives the departures from normal temperature and rain- 

 fall in New England in 1920-21. 



Table 11. — Monthly departures of temperature and rainfall in New England for 

 the fall of 1920, the winter of 1920-21, and the growing season of 1921, used 

 in connection with the 1921 summary of the gipsy moth, the brown-tail moth, 

 and the satin moth. 



DEPARTURE (IN DEGREES FAHRENHEIT) FROM NORMAL TEMPERATURE. 







1920 



1921 





Sept. 



Oct. 



Nov. 



Dec 



Jan. 



Feb. 



Mar. 



Apr. 



May. 



June. 



July. 



Aug. 



Sept. 



New England 



+ 1.7 



+6.2 



-1.4 



+ 2.9 



+3.4 



+ 3.5 



+9.4! +5.6 



+0.8 +0.0 



+ 3.0 



-1.5 +3.3 

 1 



DEPARTURE (IN INCHES) FROM NORMAL RAINFALL. 



New England 



+2.03-1.68+1.09+2.19 



-1.48-0.55-0.64 



+ 0. 77 -0. 76 -0. 53 +1. 10 -1. 02 -1. 12 



GIPSY MOTH. 



i Forth ctria dispar L.) 



The gipsy moth, during 1921 and for a series of years preceding, 

 has met with adverse conditions along its northern and northeastern 

 borders of distribution. The weather conditions in the spring are 

 usually favorable, when small larvae are being carried by the wind, 

 for its rapid dispersion in these directions, but the line of advance- 

 ment is considerabh^ impeded by the rapid change in the type of 

 forest growth, the proportion of hardwoods to conifers changing 

 rapidly. Large areas of practically clear coniferous growth are un- 

 favorable to the development of larvae, and such growth is found 

 more or less in the regions mentioned above. Another serious 

 obstacle in the more northern regions is the prevailing low tempera- 



12 By A. F. Burgess, Bureau of Entomology. 



