Fig. 259.—A, Maxilla, B, labium of Eusthenia spectabilis. (After Pictet.)
Several species of Perlidae, considered to belong to existing genera, have been found in amber. A fossil from the Eocene deposits in the Isle of Wight and another from the Miocene of Continental Europe are referred to the family. Brauer has recently described[[329]] some fossils from the Jurassic formation in East Siberia as forming three genera, now extinct, of Perlidae.
Brongniart informs us[[330]] that several fossils have been found in the Carboniferous strata of Commentry that justify us in asserting that allies of Perlidae then existed. He considers these Carboniferous Insects to have belonged to a separate family, Protoperlides. The fragments are, however, so small that we must await further information before forming a definite opinion as to these Protoperlides.
CHAPTER XVIII
AMPHIBIOUS NEUROPTERA CONTINUED—ODONATA, DRAGON-FLIES
Fam. VI. Odonata—Dragon-flies.
(LIBELLULIDAE OF SOME AUTHORS)
Elongate Insects with very mobile head and large eyes, with small and inconspicuous antennae ending in a bristle; with four elongate wings sub-equal in size and similar in texture, of papyraceous consistency and having many veinlets, so that there exists a large number of small cells. All the legs placed more anteriorly than the wings. The earlier stages of the life are aquatic; there is great change in the appearance of the individual at the final ecdysis, but there is no pupal instar.
The dragon-flies form a very natural and distinct group of Insects. All the species are recognised with ease as belonging to the family. They are invariably provided with wings in the perfect state, and many of them are amongst the most active of Insects. Their anatomy is, in several respects, very remarkable.