Some insects injurious to forests . FlG. 21.—The pine sawyer: Section of pine, showing, a1 right, mass o! borings and refuse packed under bark (bark removed) by the larva) and channels madethrough the mass by the larvae, a, Entrance hole of larva in wood; b. scored sur-faceof wood: cegg pit; (/.emergencehole. About one-half natural size. (Original.) log, boring a perfectly round exit hole usually about three-eighths ofan inch in diameter (tigs. 19, 21, 22), thereby escapingthe species in another tree or trees. g to propagate NATURAL ENEMIES. Monohammus titiUaior is preyed upon by larvae of the
Some insects injurious to forests . FlG. 21.—The pine sawyer: Section of pine, showing, a1 right, mass o! borings and refuse packed under bark (bark removed) by the larva) and channels madethrough the mass by the larvae, a, Entrance hole of larva in wood; b. scored sur-faceof wood: cegg pit; (/.emergencehole. About one-half natural size. (Original.) log, boring a perfectly round exit hole usually about three-eighths ofan inch in diameter (tigs. 19, 21, 22), thereby escapingthe species in another tree or trees. g to propagate NATURAL ENEMIES. Monohammus titiUaior is preyed upon by larvae of the coleopterousfamily Trogositidse; by the larva of an elaterid beetle o( the genusAlans, and by a species of Bracon which has been determined as newto science. None of these, however, has been powerful enough, so 54 SOME INSECTS INJURIOUS TO FORESTS. far, to appreciably thin the ranks of Monohammus. Following is thedescription, by Mr. H. L. Viereck, of the species of Bracon mentionedabove:. Fig. 22.—The pine sawyer: Emergence holes of young adults in bark, a, Natural size of emergence holes. (Original.) BRACON (MELANOBRACON) WEBBI N. SP.« Compared with ulmicola b this species differs as follows: Second dorsal abdominal segment without a triangular elevated ^X Fig. 23.— Bracon (Me-lanobracon) webbi:Dorsum of second ab-dominal enlarged.(Original.) Fig. 24.— Bracon(Melanobracon)webbi: First fourantennal enlarged.(Original.) area but with shallow, almost oblique im-pressions as diagramniatically representedin figure 23. Female: Length, llmm, exclusive of ovi-positor, which is 6mm; antennae 69-jointed;proportions and relation of first four jointsapproximately as in figure 24; joints 4 to55subequal, becoming wider than long;joints 55 to 69 becoming longer than wide, the apical joint conical. Petiole of first discoidal cell about as long as second andthird joints of antenna combined. Second dorsal abdominal segment perfectlysmooth. Type.—
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectinsectp, bookyear1910
