78 NEW YORK STATE MUSEUM 



plum prior to the flight in June to the hop vines. There have 

 been, according to careful and extended investigations conducted 

 under the supervision of the late C. V. I^iley, at that time ento- 

 mologist of the federal government, 4 to 12 generations, depend- 

 ing upon weather and other conditions. Winged adults, pro- 

 duced at the end of the season, migrate back to the plum and 

 deposit the black eggs which remain unhatched till the following 

 spring. This peculiarity in the life history of the hop aphis, 

 sugg'ests the desirability of eliminating useless wild and domestic 

 plums in the vicinity of hop yards, and also the wisdom of 

 spraying- other plum trees in the spring for the purpose ot 

 destroying the plant lice before they have had an opportunity 

 of migrating to the hop. 



Corn root aphis (Aphis m a i d 1 r a d i c i s Forbes) . A 

 subterranean species such as this, is very likel}' to escape notice 

 and this is probably the reason why it is rarely brought to at- 

 tention in New York State, though it is well known as a corn 

 pest in the Central States. Examples of this species, kindly 

 identified by Mr Pergande, through the courtesy of Dr Howard, 

 were received under date of September 29 from Mrs H. Reineck 

 of Albany, with the statement that she experienced difficulty in 

 raising- asters, owing to the abundance of plant lice upon the 

 roots. Specimens submitted for examination showed the roots 

 to be thickly clustered wath small, bluish green or reddish brown, 

 wingless plant lice about i millimeter long. Young aphids were 

 also observed feeding upon the rootlets. These pests were ap- 

 parently attended by ants, the latter probably excavating the 

 soil around the roots and possibly constructing chambers in 

 which the plant lice could winter more successfully. Injury by 

 this species in New York State appears to be so rare that, gen- 

 erally speaking, remedial measures may be considered inadvis- 

 able. It might be well in case of an infestation in the garden, 

 to pull the plants in late fall and thus destroy in large measure 

 the hibernating quarters of the aphids. Should this not be feas- 

 ible, many of these plant lice could be destroyed by treating 

 the ground with carbon bisulfid. 



Norway maple aphis ( C h a i t o p h o r u s a c e r i s Linn.) . 

 This large, yellowish green, brown marked plant louse with 

 long, hairy antennae and reddish eyes is frequently abundant 

 throughout the greater part of the season on the underside of 

 the leaves of Norway maples, and is remarkable for the large 



