. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. Fig. l.—Polygnotus hiemalis, a parasite of the Hessian fly: Adult. Greatly enlarged. (From Webster.) portation from one part of the country to another becomes easy, since all that has to be done is simply to collect twigs bearing the scales, preferably during the winter months, and carry them to non- protected regions, the parasites being dormant and pro- tected each by the scale of the coccid which it had de- stroyed; and it was specifically recom- mended that the im- portant parasite of the black scale (Sais- s
. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. Fig. l.—Polygnotus hiemalis, a parasite of the Hessian fly: Adult. Greatly enlarged. (From Webster.) portation from one part of the country to another becomes easy, since all that has to be done is simply to collect twigs bearing the scales, preferably during the winter months, and carry them to non- protected regions, the parasites being dormant and pro- tected each by the scale of the coccid which it had de- stroyed; and it was specifically recom- mended that the im- portant parasite of the black scale (Sais- setia olese Bern.), de- scribed in the article as Tomocera califor- nica, could be readily carried from California and utilized to destroy Lecanium scales in the Southeast. Excellent work in this direction has been done of late years by the Bureau of Entomology. In the study of the Hessian fly (Mayetiola destructor Say), under Prof. F. M. Webster, early-sown plats of wheat at Lansing, Mich., and Marion, Pa., in 1906, were very seriously attacked by the Hessian fly, but when ex- amined carefully at a later date fully 90 per cent of the flaxseeds (pupae) were found to have been stung by a hymenopterous parasite, Polygnotus Tiiemalis Forbes (figs. 1, 2), and to contain its developing larvae. A field of wheat near Sharpsburg, Md., was found to be infested by the fly, and examination indicated the ab- sence of the parasite. On April 8, 1907, a large num- ber of the parasitized flaxseeds from Marion, Pa., were brought to Sharpsburg and placed in the field. On July 8 an examination of the Sharpsburg field showed that the parasites had taken hold to such an extent that of the large number of flaxseeds taken and brought to the laboratory for investigation not one was found which had not been parasitized. Additional material secured from Sharpsburg in the spring of 1908 in the same locality showed all of the Hessian flies to be parasitized. In the same way excellent results have been ob
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