46 BULLETIN 1103, U. S. DEPARTMENT OF AGRICULTURE. 



ware River to the north, and to the south had extended to Merchant - 

 ville, in Camden County, and covered 48.3 square miles. In 1920 the 

 pest was discovered across the Delaware River in Philadelphia and 

 Bucks Counties, Pa., and had extended up the Delaware River on the 

 New Jersey side as far as Burlington. In 1920 the area infested had 

 reached 103.3 square miles; in 1921 the pest had spread to the south 

 in New Jersey into Gloucester County, and to Medford and North 

 Hampton in Burlington County. In Philadelphia County, Pa., it 

 had extended to Frankford and Bustleton, and had touched the south- 

 ern boundary of Montgomery County, while to the northeast it had 

 extended to Bristol in Bucks County. It is now known to cover a 

 territory of 270.1 square miles. (Fig. 25.) 



The areas given for 1916, 1917, and 1918 are not necessarily exact 

 since the earlier surveys were more or less general. The areas indi- 

 cated for 1919, 1920, and 1921, however, are quite accurate, since very 

 careful scouting was carried on during these years. 



Beetles were discovered at two isolated localities to the southwest 

 in Philadelphia County, one near the Delaware River, southwest of 

 Elmwood, and the other on the west shore of the Schuylkill River in 

 Fairmount Park. 



SATIN MOTH. 



(Stilpnotia salicis L. ) n 



The satin moth is common in Europe and is mentioned briefly in the 

 writings of many European entomologists. It is reported as com- 

 mon in England and Ireland, its range extending from Spain to 

 eastern Asia and as far north as Norway. One authority states that 

 it occurs from Lapland to the middle of Italy and from England to 

 Peking, China. 



About July 1, 1920, a crew of men employed by the metropolitan 

 park department found a number of Carolina poplar trees located 

 on the Fellsway at the Maiden and Medford City line, just north of 

 Boston, Mass., that were being defoliated. S. S. Grossman, of the 

 Bureau of Entomology, identified the insect as the satin moth, and 

 this identification was later confirmed by the United States National 

 Museum. 



Scouting was immediately started and, as a result of this work, 

 by the fall of 1920 the insect was known to occur over an area of 

 642 square miles including 60 towns in Massachusetts and 4 in New 

 Hampshire. Inasmuch as large larvae and pupae were found in many 

 of the towns, these towns were evidently infested the previous year 

 (1919). During the year 1921 this insect was numerous in several 

 towns and cities about Medford and Maiden, where plantings of 

 poplar suffered almost complete defoliation. Beyond this central 



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



