. The Cambridge natural history. Zoology. CADDIS-FLIES 485 wings, while in _Thamastes the posterior wings are absent in These anonmlies are. Fig. 330.—Oxyethira costaKs. A, Larva in case ; B, cases fastened to leaf for pupation. (After Klapalek.) of both sexes. at present quite inexplicable; and we may here mention that we are in complete ignorance as to the functional importance of many of the peculiarities of the Phryganeidae. We do not know why the mouth is reduced from the normal state, the maxillary palpi being, on the other hand, extraordinarily developed ; we do not know the importance
. The Cambridge natural history. Zoology. CADDIS-FLIES 485 wings, while in _Thamastes the posterior wings are absent in These anonmlies are. Fig. 330.—Oxyethira costaKs. A, Larva in case ; B, cases fastened to leaf for pupation. (After Klapalek.) of both sexes. at present quite inexplicable; and we may here mention that we are in complete ignorance as to the functional importance of many of the peculiarities of the Phryganeidae. We do not know why the mouth is reduced from the normal state, the maxillary palpi being, on the other hand, extraordinarily developed ; we do not know the importance of the numerous spines and of the spurs on the legs, nor of the hairs on the wings, although these are amongst the most characteristic of the special features of this group of Insects. Fossils.—Abundant remains of Phryganeidae belonging to the Tertiary epoch have been discovered. They are common in amber, and it is a remarkable fact that a larval case has been found in amber. This seems almost inexplicable, except on the assumption that such larvae were of arboreal habits, a condition that, at the present time, must be excessively rare, though the terrestrial habits of Enoicyla warrant us in believing it may occur. In the Tertiary Lake Basin at Colorado the remains of Phryganeidae in the imago state are extremely abundant, so that it is curious that but few such remains have been found in Europe. In Auvergne the so-called indusial limestone, which is two or three yards thick over a wide area, is considered to be composed chiefly of the cases of larvae of this family. In the Mesozoic epoch some wings found in the lower Purbeck strata are considered to be those of Phryganeidae; similar wings have been found in the Lias, but this is the only evidence of the existence of the family at that period except a tube, supposed to be a larval case, detected in the Cretaceous of Bohemia. Earlier than this nothing has been discovered that can be connected with the family, so that at pres
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1895
