Читать книгу A Text-book of Entomology онлайн

18 страница из 232

The deutomalæ (gnathochilarium), or second pair of diplopod jaws, are analogous to the labium or second maxillæ of insects, forming a flattened, plate-like under-lip, constituting the floor of the mouth (Fig. 6). This pair of appendages needs farther study, especially in the late embryo, before it can be fully understood. So far as known, judging by Metschnikoff’s work on the embryology of the diplopods, these myriopods seem to have in the embryo but two pairs of post-antennal mouth-parts, which he designated as the “mandibles” and “labium.” Meinert, however, regards as a third pair of mouth-parts or “labium” what in our Fig. 7 is called the internal stipes (stip. i.), behind which is a triangular plate, lamina labialis (lam. lab), which he regards as the sternite of the same segment.

Fig. 7.—Deutomala of Julus, the lettering as in Fig. 6.

Fig. 8.—Head of Scolopendra, seen from beneath, showing the “mandible” (protomala) with its cardo (card.) and stipes (st.), also the labrum and epilabrum.