Читать книгу A Text-book of Entomology онлайн

160 страница из 232

At the base of the hind wings of Trichoptera and in the lepidopterous Micropteryx there is an angular fold (jugum) at the base of each wing (Fig. 138); that of the anterior wings is retained in Eriocephala and Hepialidæ.

Fig. 138.—Venation of fore and hind wings of Micropteryx purpurella: j, jugum, on each wing; d, discal vein; the Roman numerals indicate veins I.-VIII. and their branches.

In the wings of Orthoptera as well as other insects, the fore wings, especially, are divided into three well-marked areas, the costal, median, and internal; of these the median area is the largest, and in grasshoppers and crickets is more or less modified to form the musical apparatus, consisting of the drum-like resonant area, with the file or bow.

The squamæ.

More recently (1890 and 1897) Osten-Sacken recommends “squamæ; in the plural, as a designation for both of these organs taken together; squama, in the singular, would mean the posterior squama alone, and antisquama the anterior squama alone;” the strip of membrane running in some cases between them, or connecting the squama with the scutellum, should be called the post-alar membrane. By a mistake Loew, and others following him, used the word tegula for squama, but this term should be restricted to the sclerite of the mesothorax previously so designated (Fig. 90, A, t). The squama or its two subdivisions has also by various authors been termed alula, calypta, squamula, lobulus, axillary lobe, aileron, cuilleron, schuppen, and scale. (Berlin Ent. Zeitschrift, xli, 1896, pp. 285–288, 328, 338.)