Lign. 183. Fossil Insects. Tertiary. Aix in Provence.
| Fig. | 1.— | Tettigonia spumaria. |
| 2.— | Mycetophila; the body distended by pressure. | |
| 3.— | Lathrobium. | |
| 4.— | Allied to Penthetria holosericea. The hinder legs are broken off, and one of them reversed, so that the tarsi nearly touch the thigh; the palpi are long and perfect; the antennæ are remarkably distinct. | |
| 5.— | Liparus; resembling L. Punctatus. |
Fossil Insects of Œningen.—In the immediate vicinity of Œningen, near Constance, on the banks of the Rhine, there is the basin of an ancient lake, filled up with marls and limestones, presenting a fine example of a lacustrine formation, and abounding in fossil Fishes, Reptiles, Plants, Shells, Crustaceans, and Insects.[501] These Insects are often in an admirable state of preservation, and occur in the different stages of larva, pupa, and imago. The pupa of a Libellula shows the mask, insertion of the legs, and the spiracula. Some belong to genera, the species of which frequent marshy plants of the same kind as those which are found associated with the insects; and it seems probable that they fell into the lake from the plants which grew on its borders, and became enveloped in the fine mud or sediment. Numerous species of several genera of Ants also occur in these deposits of Œningen and at Radoboj in Croatia.[502]
[501] See the Memoir by Sir R. I. Murchison on the lacustrine formation at Œningen, near Constance, Geol. Trans, new series, vol. iii. p. 277.
[502] See Prof. O. Heer’s Memoir, translated in the Quart. Journ. Geol. Soc. vol. vi. pt. ii. p. 61; and his History of Insects, ibid. p. 68.
FOSSIL CADDIS-WORM.
Fossil Larvæ of Phryganea. Ly. p. 185.—The Caddis-worm, so well known to all the brethren of the angle, is the larva of the winged insect termed Phryganea, and is abundant at the bottom of fresh-water streams and lakes; the cases, like those of the marine Sabella ([p. 385], fig. 6), are always studded over with extraneous bodies, cemented together by a glutinous secretion to the silken integument, or case, which encloses the lava. Some species are coated with pieces of stick or straw, others with minute shells, as planorbis, bithinia, and the like; and when the larvæ have passed into the perfect state, their cases, or indusiæ, remain. Many of the Tertiary fresh-water limestones of Auvergne are almost wholly composed of the indusiæ of Caddis-worms, cemented together by calcareo-siliceous matter into stone, which is employed for building, and is called indusial limestone (Wond. p. 273). These limestones are associated with marls abounding in fresh-water shells and cyprides; the whole assemblage presenting all the stratigraphical and zoological characters of a lacustrine formation. "If," says Mr. Scrope,[503] "we consider that repeated strata, of five or six feet in thickness, almost entirely composed of these tubes, once extended over a district presenting a surface of many hundred square miles, we may have some idea of the countless myriads of minute beings which lived and died within the bosom of that ancient lake."
[503] On the Geology of Central France, by G. Poulett Scrope, Esq. 4 to. 1827.