. The Cambridge natural history. Zoology. CADDIS-FLIES 481 tribution is, however, by no means peculiar to thern, for a similar discontinuity of distribution exists in numerous other groups of Insects, and even in other divisions of the Phryganeidae. The Phryganeides ahnost without exception inhabit still waters, and it is more specially to them that the brief sketch of meta- morphosis given in the preceding pages will be found to apply. The larva always has the respiratory filaments simple and thread-Hke, thoiigh elongate, and lives in a case that it carries about; this case is open at both en
. The Cambridge natural history. Zoology. CADDIS-FLIES 481 tribution is, however, by no means peculiar to thern, for a similar discontinuity of distribution exists in numerous other groups of Insects, and even in other divisions of the Phryganeidae. The Phryganeides ahnost without exception inhabit still waters, and it is more specially to them that the brief sketch of meta- morphosis given in the preceding pages will be found to apply. The larva always has the respiratory filaments simple and thread-Hke, thoiigh elongate, and lives in a case that it carries about; this case is open at both ends, and the larva is said to occasionally cut off the end having the least diameter and increase the other end, thus accommodating the habitation to its own growth. Limnophilides.âThese Insects have only three, instead of four, joints in the maxillary palpi, but in most â other respects agree with the Phryganeides. There is, however, greater variety in the habits of the larvae, though all live in free cases. In the genus Enoicyla (Fig. 326) we meet with the anomaly of a Trichopter- ous Insect that lives amongst moss and dead leaves, far away, it may be, from water. The cases of the Limnophilides are constructed of a great variety of materials, and are often decorated with shells containing Hving inmates. In the genus Apa- tania the phenomenon of parthenogenesis is thought to occur, there being at least two species in which no male specimen has ever been discovered, though M'Lachlan has made special efforts to discover the sex of A. muliehris. It should, however, be stated that these species have not been ex- tensively investigated; A. arciica has been detected in the Arctic regions, and A. muliehris has occurred in several localities in Europe, in Britain chiefly near Arundel in a lake of intensely cold water. VOL. V 2 I. Fig. 326. â Metamorphoses of Enoicyla pusilla. (After Eitsema.) A, Case of full-grown larva ; B, larva aud case magiiilied ; C, larva extracted ; D, wingle
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1895
