. The Cambridge natural history. Zoology. LAMELLICORNIA STAG-BEETLES 193 provided with highly-developed stridulatory structures. No auditory organ is known, unless the peculiar spiracles be such. Fam. 2. Lucanidae (Stag-beetles).—Labrum indistinct, fixed ; mentum not excised; antennae not curled in rejwse, with hut little coadaptation of the terminal joints ; the elytra entirely cover the dorsal surface of the abdomen. The Stag-beetles are well known ou account of the extraordinary development of the mandibles in the male sex, these organs being in some cases nearly as long as the whole of the
. The Cambridge natural history. Zoology. LAMELLICORNIA STAG-BEETLES 193 provided with highly-developed stridulatory structures. No auditory organ is known, unless the peculiar spiracles be such. Fam. 2. Lucanidae (Stag-beetles).—Labrum indistinct, fixed ; mentum not excised; antennae not curled in rejwse, with hut little coadaptation of the terminal joints ; the elytra entirely cover the dorsal surface of the abdomen. The Stag-beetles are well known ou account of the extraordinary development of the mandibles in the male sex, these organs being in some cases nearly as long as the whole of the rest of the Insect, and armed with projections or teeth that give the Insects a most formidable appearance. So far as we have been able to discover, these structures are put to very little use, and in many cases are not capable of being of service even as weapons of offence. The males are usually very much larger than the females, and are remarkable on account of the great variation in the stature of different indi- viduals of the same species; correlative with these distinctions of individual size we find extreme differences in the development of the head and mandibles. Moreover, the small male specimens exhibit not merely reductions in the size of the mandibles, but also show considerable differences in the form of these parts, due, in some cases, apparently to the fact that only when a certain length of the mandible is attained is there any development of certain of the minor projec- tiiius: in other cases it is not possible to adopt this view, as the small mandibles bear as many Fig. and prothorax of form,s of the male of projections as the large a stag-beetle ; Homoeoderus indlyi (Africa). A, forms do, Or even more. Large, B, intermediate, C, small forms. (From a ^ , q-npHes these photograph hy E. Oberthiir.) ^^ ^aCU speClCS tnese variations fall, in the. majority of cases, into distinct states, so that entomologists describe them as " forms," the lar
Size: 2197px × 1138px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1895
