754 EXPEEIMENT STATION EECORD. 



respiratory action of the plant tissues." Attacks on the tree from year to year 

 also materially reduce its vitality. 



The life history of the walnut aphidids in California in brief is summarized 

 by the author as follows: "A week or so before the buds open on the trees in 

 the spring the aphidids begin to hatch from the winter eggs. As soon as the 

 young foliage appears the ' lice ' settle on it, and after feeding for a month or 

 so become adults. These stem mothers are always winged and like plant lice 

 of later generations are capable of migrating to other trees and orchards. As 

 soon as they are fully developed they produce young parthenogenetically. These 

 second-generation young become mature in three weeks and in turn produce 

 young. The individuals of the third and subsequent generations of summer 

 mature in about 16 days. On early-leafing varieties there are 10 or 11 

 viviparous generations in the year while on late varieties there are 8 or 9. The 

 production of the sexual generations is prolonged over four months, these forms 

 first appearing in July. After the sexes (comprised of the winged male and the 

 wingless female) mate, the female repairs to the twigs and limbs of the tree, 

 there to deix)sit her eggs. Winter is passed in the egg stage only." 



Of the many predatory enemies of the walnut plant lice the ashy-gray lady 

 beetle (Olla aidominalis) is said to be the most important. As regards remedial 

 measures the author finds that winter spraying directed against the eggs is the 

 easiest to apply, and that high trees can be reached by a winter wash with 

 ease. " Lime-sulphur and crude-oil emulsions are effective, especially the first 

 named. The spray should be directed all over limbs and twigs so as to cover 

 every part. If it Is necessary to spray in spring or summer, a combination of 

 2 per cent distillate-oil emulsion and commercial tobacco extract No. 2(1: 1,500) 

 will prove effective provided it be applied under a pressure of at least 150 lbs. 

 and the spray directed on the nuts and underside of the leaves." 



A bibliography of literature relating to these aphids is appended, 



New or little-known species of Aphididae, J. J. Davis (Canad. Ent., J^G 

 {WW, Nos. 2, pp. U-51, figs. 13; 3, pp. 77-87, figs. 22; 4, PP. 121-134, figs. 19; 

 5, pp. 165-173, fig. 1; 7, pp. 226-236, figs. i2).— Species here described as new 

 Include Macrosiphum creclii from alfalfa in Utah, Nevada, and Washington; 

 M. coryli, which lives gregariously on the underside of the leaves and tender 

 terminal shoots of hazel {Corylus americana), collected at La Fayette, Ind., 

 and Chicago, 111.; M. vouvfuscce from crested wild buckwheat {Polygonum 

 cHsiatum) and curled leaf dock {Rumex crispus) in Indiana, from Rumex and 

 P. cristntum in Wisconsin, and from Rumex in Missouri ; Symdohius albasiphus 

 fi'cm white oak in Illinois, Indiana, Missouri, and Virginia ; and Aphis pseudo- 

 brassiccB from cabbage in New York, radish, turnips, kale, rape, and mustard 

 in Indiana, and turnips in Texas. 



Contribution to the study of the biology of the black aphis of the beet 

 root, L. Gaumont {Compt. Rend. Acad. Sci. [Paris], 157 {1913), No. 22, pp. 

 1092-1094; Rev. Phytopath. Appl, 1 {1914), No. 16-17, pp. 4» 5; als. in Rev. 

 Appl. Ent., 2 {1914), Ser. A, No. 4, pp. 236, 237).— Aphis euonymi causes con- 

 siderable damage to beets in north and central France nearly every year. This 

 aphidid passes the winter in the egg stage on Japanese spindle-trees, which are 

 very numerous in parks and public gardens, as well as on the European spindle- 

 tree {Eiionymus europccus) and guelder-rose {Vibitrnitiri opuliis). 



The author observed at the end of October a field of beet roots in which the 

 aphid was still present, both in parthenogenetic and sexual forms, and in which 

 females were laying eggs at the bases of the leaves. Attention is called to the 

 fact that the eggs which remain in the collar hatch in the cellar after the 

 roots are stored and in the spring spread to Rumex, Chenopodium, and other 

 wild plants. 



