Insect pests of farm, garden and orchard . Fig. 94.—The wheat saw-fly borer{Cephus pygmceus Linn.): a, out-line of larva, natural size; b, larva,enlarged; c, larva in wheat-stalk,natural size; d, frass; e, adultfemale;/, Pachyonerufs colcitrdtor,female, a parasite — enlarged.(After Curtis, from Insect Lift.^) INSECTS INJURIOUS TO SMALL GRAINS 131 following year. This is done by cutting the straw circularlyon the inside, nearly severing it a short distance, varying fromone-half to one-inch, from the ground. If the wheat were grow-ing wild, the winter winds would cause the stalk to break atthis
Insect pests of farm, garden and orchard . Fig. 94.—The wheat saw-fly borer{Cephus pygmceus Linn.): a, out-line of larva, natural size; b, larva,enlarged; c, larva in wheat-stalk,natural size; d, frass; e, adultfemale;/, Pachyonerufs colcitrdtor,female, a parasite — enlarged.(After Curtis, from Insect Lift.^) INSECTS INJURIOUS TO SMALL GRAINS 131 following year. This is done by cutting the straw circularlyon the inside, nearly severing it a short distance, varying fromone-half to one-inch, from the ground. If the wheat were grow-ing wild, the winter winds would cause the stalk to break atthis point; and thus the insect after it had reached the adultstate could easily escape; while l)ut for this cut it would be veryliable to Ik^ imprisoned in the straw. Ordinarily, the straw iscut by the reaper before it becomes broken; but a strong wind. Fig. 95.—The western grass-stem saw-fly {Cephus occidentalis): a, larva;b, female saw-fly; c, grass-stem showing work, c, enlarged, a, b, moreenlarged. (After Marlatt, U. S. Dept. Agr.) just before harvest will cause a large number of stalks to becomebroken, much as if affected by the Hessian fly. After the circular cut has been made, the larva fills thecavity of the straw just below it for a short distance with a plugof borings. Between this plug and the lower end of the cavityof the straw there is a place about one-half an inch in is here that the insect passes the winter. This cell is linedwith silk so as to form a warm cocoon. Here the larva passesthe winter and changes to a pupa in March or April. The adultinsect emerges early in May. The adults arc four-winged insects, 132 INSECT PESTS OF FARM, GARDEN AND ORCHARD and are popularly known as saw-llics on account of tlic saw-likeovipositor of the fcni;ilc, by means of which she inserts hereggs in the 1 issue of tlic |)l
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Keywords: ., bookcentury1900, bookdecade1910, bookpublisheretcet, bookyear1912
