culty that has been experienced in its treatment, pea growers during 

 the first year of its ravages having met with nearly complete failure in 

 the remedial measures applied. 



Although garden and field peas are the crops most injured by this 

 plant-louse, sweet peas, red and crimson clover, as well as vetches 

 and tares ^ are affected, and in some cases have been damaged. 

 Attack begins on the young vines ; the lice gather in clusters at first 

 under and within the terminals, and as the leaves become covered 

 they attack also the stems, and by their numbers and voracity sap 

 the life of the plant. Whole areas of vines are frequently seen cov- 

 ered with the lice, which in a very few weeks are able to destroy a 

 crop. Attack is seldom noticed until May^ in the more southern 

 States in which the insect is found, and a little later in its more north- 

 ern range. 



The complete life history of this species is not known, but like other 

 plant-lice it produces many generations each year. 



According to present knowledge, the pea louse hibernates on clover, 

 particularly crimson clover, from Delaware southward. In the Dis- 

 trict of Columbia it winters also on vetch. From these plants the lice 

 spread by fiight in April and May to peas, which they attack while 

 young. 



As with other plant-lice, the females at certain peri'ods produce living 

 young. These attain maturity in from ten to fifteen days, and possibly 

 in less time in the hottest weather. Young that were born March 4 

 reached full maturity (winged form) March 16, or twelve days from the 

 time of birth, and reproduced young three days later. 



As an instance of the rapid reproductive powers of this insect, Pro- 

 fessor Johnson's estimate is interesting. He states that females produce 

 from 110 to 120 young; and that in one case where lice were observed 

 on the first of May the fields were abandoned on account of ravages 

 three weeks later. Calculating from the average number of insects 

 produced each day, which is six, one individual would become the pro- 

 genitor of 423,912 of these lice. 



NATURAL ENEMIES. 



The efficiency of natural agents in the destruction of plant-lice is 

 so well known that it has been hoped that some one or more of the 

 many species observed to attack the destructive green pea louse would 



^A considerable number of alternate food plants has been observed for 

 Nectaro'phoru pisi Kalt. in Europe. 



-The present year (1901) Mr. Samuel R. Haynes, Portsmouth, Va., reported 

 tlie presence of this species in that locality about April 7. During the second 

 week of May the writer found the insect numerous on crimson clover and vetches 

 at Wasliington, D. C, and May 14 it was reported at work upon peas in the' 

 District of Columbia, near the Mar3'land State line. 



