. A manual for the study of insects. Insects. H YMENOP TERA. 623 the species are mostly of considerable size, and here belong the larger of the parasitic Hymenoptera. In this family the wings are furnished with several closed cells ; the fore wings have a stigma; and cells V^ and ist V^ are separate (Fig. 748). The largest members of the family belong to the genus Thalessa. These are remarkable-looking insects, with long, slender bodies and three long hairs at the end of the body. Two of these hairs form a sheath for the third, which is the ovipositor. This ovipositor, although apparently mere
. A manual for the study of insects. Insects. H YMENOP TERA. 623 the species are mostly of considerable size, and here belong the larger of the parasitic Hymenoptera. In this family the wings are furnished with several closed cells ; the fore wings have a stigma; and cells V^ and ist V^ are separate (Fig. 748). The largest members of the family belong to the genus Thalessa. These are remarkable-looking insects, with long, slender bodies and three long hairs at the end of the body. Two of these hairs form a sheath for the third, which is the ovipositor. This ovipositor, although apparently merely a thread, is really composed of three pieces placed parallel, one above and two below, and securely locked together. Near the end of them are ridges like those on a file, and between them is a passage through which the ^gg is forced when it is laid. Thalessa lunator (Tha-les'sa lu-na^tor) is one of the larger of our Ichneumon-flies. Its body is two and one half inches long, and it measures nearly ten inches from the tip of the antennae to the tip of the ovipositor. It is a parasite of the wood-boring larva of the Pigeon Horn- tail. When a female finds a tree infested by this insect she selects a place which she judges is opposite a Tremex-bur- row, and, elevating her long ovipositor in a loop over her back, with its tip on the bark of the tree (Fig. 749), she makes a derrick out of her body, and proceeds with great skill and pre- cision to drill a hole into the tree. When the TremeX-burrOW is Fig. t^^,—Thalessa lunator. reached she deposits an egg in it. The larva that hatches. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Comstock, John Henry, 1849-1931; Comstock, Anna Botsford, 1854-1930. joint author. Ithaca, N. Y. , Comstock Pub. Co.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectinsects, bookyear1895
