| 释义 |
‖ ptilinum Entom.|ˈptɪlɪnəm|
[mod.L., ad. F. ptiline (J. B. Robineau-Desvoidy Essai sur les Myodaires (1830) i. 10), arbitrarily f. Gr. πτίλ-ον down, a plumelet.]
A peculiar structure in some dipterous insects: see quots. Hence ˈptilinal a.
1853F. Walker Insecta Britannica: Diptera II. 2 The ptilinum is a soft membrane, which in many species, and especially in the newly-hatched flies, appears between the antennæ and the front. 1899Cambr. Nat. Hist. VI. 442 About one-half of the Diptera possess a peculiar structure in the form of a head-vesicle called ‘ptilinum’. In the fly emerging from the pupa this appears as a bladder-like expansion of the front of the head; being susceptible of great distension, it is useful in rupturing the hard shell in which the creature is then enclosed. In the mature fly, the ptilinum is completely introverted and can be found only by dissection. 1925A. D. Imms Gen. Textbk. Entomol. iii. 593 The Ptilinum or frontal sac is a characteristic cephalic organ of Cyclorrhapha and its presence is indicated externally by the arched frontal or ptilinal suture. 1962Gordon & Lavoipierre Entomol. xxvii. 171 Having emerged from the puparium the insect pushes its way up through the soil to the surface by the alternate inflation and deflation of the ptilinum. 1969R. F. Chapman Insects xxii. 441 Once the fly has hardened the ptilinum is no longer eversible and the muscles associated with it degenerate. Its position is indicated in the mature fly by the ptilinal suture. |