. Bulletin of the Department of Agriculture. Agriculture. THE PEA APHIS WITH RELATION TO FORAGE CROPS. 53 labris Muls., Adalia bipunctata L., and CMlocorus bivulnerus Muls. Both larvse and adults feed on the plant lice. The larvae of the syrphid flies (Syrphida?), more generally known under the name of "sweat bees," are important enemies of the pea. Fig. 1~>—Allograpta obliqua, a syrphid fly the larva of which preys upon Macrosiphvm pisi. (Original.) aphis. The larvse are sluglike and attack the aphis by piercing it and sucking the body juices. Each larva is capable of devour
. Bulletin of the Department of Agriculture. Agriculture. THE PEA APHIS WITH RELATION TO FORAGE CROPS. 53 labris Muls., Adalia bipunctata L., and CMlocorus bivulnerus Muls. Both larvse and adults feed on the plant lice. The larvae of the syrphid flies (Syrphida?), more generally known under the name of "sweat bees," are important enemies of the pea. Fig. 1~>—Allograpta obliqua, a syrphid fly the larva of which preys upon Macrosiphvm pisi. (Original.) aphis. The larvse are sluglike and attack the aphis by piercing it and sucking the body juices. Each larva is capable of devouring many aphides in rapid succession. Johnson reports (1899) that one grower in Maryland, when separating peas, sieved out about 25 bushels of syrphid larva?, mostly of the spe- cies Allograpta obliqua Say (figs. 15, 16), which is illus- trative of the abundance of these larvae at times. The ft ^a?)\ adult flies are everywhere abundant in summer, and ^ li^ T especially in the neighborhood of heavy aphis infesta- J V'%"7<6 tions. They hover in the air and at brief intervals fly '<T"||p?V, rapidly, but only for short distances. Folsom (1909) enumerates eight species as attacking Macrosiplium pisi, namely, Ocyptamus (BaccJia) fuscipennis Say, PlatycMrus quadratus Say, Syrplius americanus Wied., .1.^.1 iI S. ribesii L., Allograpta obliqua Say, Mesogramma mar- ginatum Say, M. politum Say, and Spliaeroplioria cylin- drica Say. Three species of lace-wing fly larvae (Chrysopidae), namely, Chrysopa oculata Say, C. rufilabris Burm., and fig. C. plorobunda Fitch, feed on this plant louse. They grapta obliqua: predacious in the larval stage, as is the case with Larva. Much * . . enlarged, the syrphids. The larvae are provided with a pair of (From Metcaif.) follow bow-shaped mandibles or j aws, with which they grasp the aphis and through which its juices are sucked. The adults are pale green insects with relatively large lacelike wings, and from this character the
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectagriculture, bookyear
