448 MAINS AGRICULTURAL EXPERIMENT STATION. 



aa. Abdomen of adult female without a pygidium. 



b. No anal cleft nor triangular plates at posterior end of abdomen 



of female; antennae and legs present in adult. 

 c. Newly hatched nymphs with rows of dorsal spines, adult 

 surrounded by cotton but dorsally naked. 



Gossyparia spuria. 



cc. Newly hatched nymphs without dorsal spines; antennae 9 



jointed, 6 setae in anal ring. Phenacoccus. 



d. "Tibia nearly 3 times as long as the tarsi." P. acericola. 



dd. "Tibia less than twice as long as the tarsi." P. dearnessi. 



bb. Adult female with an anal cleft and triangular plates at posterior 



end of abdomen. 



c. Adult female is naked, more or less convex and hemispherical, 



scale-like, hard when mature. Hulecanium corni. 



cc. Secretion of female more or less cottony, ovisac posterior 



and adherent to twig and leaf. Pulvinaria vitis. 



PLANT LICE. 



Aphidae* 



Among the most troublesome of the Aphides of the season 

 were rather conspicuously those upon plum trees, currant 

 bushes, apple trees, and elms. More detailed records of these 

 either have been or will be given in other publications, but a 

 few items seem to fall naturally into this bulletin. 



Especial preparations had been made for migration tests 

 with Prociphilus venafuscus but only a few colonies on Praxi- 

 nus were found this season and those were too well attended by 

 predaceous enemies to be profitable for experimental purposes. 

 A few colonies of this species were also found upon Forsythia 

 bushes on the campus. Spring migrants were placed upon 

 Balsam Fir seedlings in pots and in one instance a few of the 

 progeny stationed themselves upon exposed roots and fed, nor- 

 mally secreting honeydew and white wax for a few days. These 

 soon died and no conclusive data was obtained. Late in the 

 season apterous aphides which I believe to be this species were 

 abundant upon roots of young Balsam Firs near Orono but no 

 pupae were found and no developing winged forms so that 

 again the conclusive link was lacking. 



Aphis bakeri was taken on Crataegus in the spring and the 

 progeny of the spring migrants responded properly to clover 

 tests, maturing and producing there quite content. A colony 

 of this species was brought into the Station on sweet peas. 



* Notes by Edith M. Patch. 



