Читать книгу A Text-book of Entomology онлайн

171 страница из 232

These observations on two widely separate groups of Diptera were confirmed by Landois, and afterwards by Pancritius, for the Lepidoptera, by Ganin for the Hymenoptera, by Dewitz for Hymenoptera (ants) and Trichoptera; also for the Neuroptera by Pancritius. In the ant-lion (Myrmeleon formicarius) Pancritius found no rudiments of the wings in larvæ a year old, but they were detected in the second year of larval life, and do not differ much histologically or in shape from those of Lepidoptera. In the Coleoptera and Hymenoptera the imaginal buds appear rather late in larval life, yet their structure is like that of Lepidoptera. In Cimbex the rudiments of the wings are not found in the young larva, but are seen in the semipupa, which stage lasts over six weeks.

Fig. 143.—Section of the same specimen as in Fig. 142, but cut through the second pair of wings (w): i, mid-intestine; h, heart; fb, fat-body; l, leg; n, nervous cord.

The general relation of the rudiments (imaginal buds) of the wings of a tineid moth to the rest of the body near the end of larval life may be seen in Figs. 142, 143 (Tinea?), the sections not, however, showing their connection with the hypodermis, which has been torn away during the process of cutting. That the wing is but a fold of the hypodermis is well seen in Fig. 144, of Datana, which represents a much later stage of development than in Figs. 142 and 143, the larva just entering on the semipupa stage.