A SYNOPSIS OF THE APHIDIDAE 111 



The summer host plant of this aphid is as yet unknown in Cali- 

 fornia. During June, 1915, the author spent many hours in search 

 of this host plant, but to no avail. He examined every kind of plant 

 within two or three hundred yards of the apple orchard at Stanford 

 University, but on none was he able to find any aphid that could pos- 

 sibly be the summer form of Aphis malifoliae Fitch. Bremner reports 

 having found isolated individuals on pigweed (Amaranthus retro- 

 flex'us) in Sonoma County, but believes this to be accidental for he has 

 never observed them to deposit young on this plant. Davidson writes 

 that he has been able to colonize them in the laboratory on the leaves 

 of plantain (Plantago spp.), in fact has been able to have them repro- 

 duce in such large numbers as to kill the plants. On May 28, 1915, 

 the author placed two alate females from apple leaves on each of two 

 specimens of Plantago hirtella under bell jars in the laboratory at 

 Stanford University. On returning to town on June 10 he found that 

 the plants were in a dying condition, owing to a lack of proper care 

 during his absence. However, he found many young lice present, all 

 of which were alive and feeding. The adult alate females had already 

 died. By June 16 the lice had moulted once, but then the plants were 

 practically dead. He left Stanford within a few days not to return, 

 so was unable to begin fresh experiments along this line. In his search 

 for the alates in the field he was particularly careful to examine 

 closely every plantain plant in the vicinity, but could find no trace of 

 this aphid on them. Davidson also reports the same lack of success. 

 Consequently, although the alates will deposit young on plaintain 

 in the laboratory it cannot very well be the natural summer host in 

 this state. Baker and Turner have proven that Plantago lanceolata 

 is the summer host in Virginia. W. H. Britain has observed a definite 

 migration to plaintain in Nova Scotia (Proc. Ent. Soc. Nova Scotia, 

 vol. 1, pp. 16-30, 1915). Incidentally he has been able to breed it 

 throughout the summer on apple. In Orange County, in the vicinity 

 of the known infestations, the author was unable to find any plaintain 

 whatsoever. On inquiring of Roy K. Bishop, the county horticultural 

 commissioner, it was learned that plaintain is very scarce in that 

 county, except very near to the coast, and that it is exceedingly doubt- 

 ful if there is any in the vicinity of the known aphid infestations. 



The fall migrants begin to return to the apple some time during 

 the fall and deposit living males and females. From Nevada County 

 comes the report that the migrants return to the apple "between the 

 twentieth of September and the first of October. ' ' Davidson has taken 

 the oviparous females and the alate males on December 5 (1912) at 



