Dec., '08] ENTOMOLOGICAL NEWS. 485 



last apterous viviparous generation is maturing and bringing 

 forth an excessively numerous progeny which winter among the 

 leaves on the ground, a generation of large winged forms ap- 

 pears upon the alder stem in flocculent masses containing some- 

 times a few apterous forms and sometimes in clusters where the 

 apterous forms are the more numerous. 



These winged forms take flight without producing young 

 upon the alder, and early in September in those seasons when 

 the species 1 is particularly numerous the flig'ht of this Pemphigus 

 is so considerable as to give the appearance of a slight snow 

 storm in the air. The bodies of the migrants are dark but the 

 wings are whitish and powdered and much of the flocculent wax 

 is retained upon the abdomen even in flight. 



One such flight was noticed September i, 1905 and several in 

 late August and early September, 1908. On account of the ex- 

 cessive numbers of syrphus maggots and the larvae of the wan- 

 derer butterfly, Feniseca tarquinius* in 1906 the alder blight 

 was nearly exterminated in the vicinity of Orono that season 

 and during 1907 the colonies were not plentiful. This present 

 season, however, they are again numerous and at the time of 

 their flight a winged Pemphigus was seen to be congregating 

 in conspicuous numbers upon the trunks of maple on the cam- 

 pus, particularly Acer dasycarpum Ehrh. and the ornamental 

 cut leaved maples. Microscopic examination showed no distinc- 

 tion between the Pemphigus newly alighting upon the maple 

 trunks and these taking flight from the alder and it was with 

 intense interest that the following observations were made. 



August 27, 1908. Winged viviparous Pemphigus covering 

 the trunk of cut leaved maple. They are seeking the crevices 

 and rough places in the bark and are making no attempt to feed. 



August 28, Pieces of bark torn back from maple trunk show 

 the winged viviparous Pemphigus and their numerous progeny, 

 minute forms which under a lens prove to be the sexual forms, 

 many of them being in copulation. 



August 28. Winged Pemphigus tcssellata removed from 

 alder before flight and placed in cage upon twigs of maple 



* Me. Agr. Exp. Sta., Bui. No. 134, pp. 216-217. 



