. Bollettino del museo di zoologia comparativa a Harvard College. Zoologia. Le figure da 4 a 6. Serie di confronto per dimostrare la correlazione di riduzione occhi habitat e restrizione. Fig. 4, pag. consobr/nus, ampio, epigean. Fig. 5, pag. shapardi, gamma in western Ozarks, edaphophilic. Fig. 6, pag. hirtus, Mammoth Cave regione del Kentucky, troglobite. Tutte disegnate in scala. in possesso del pigmento dell'occhio. In tutti i casi di riduzione degli occhi, solo il troglobites del gruppo hirtus, e gesso e troglo- mexicanus hanno perso la pigmentazione dell'occhio. La pigmentazione è presente nel tioglo- morde cocytu

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. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. Figures 4-6. Comparative series demonstrating correlation of eye reduction and habitat restriction. Fig. 4, P. consobr/nus, wide ranging, epigean. Fig. 5, P. shapardi, range in western Ozarks, edaphophilic. Fig. 6, P. hirtus, Mammoth Cave region of Kentucky, troglobite. All drawn to same scale. in the possession of eye pigment. In all cases of eye reduction, only the troglobites of the hirtus group, and gypsum and troglo- mexicanus have lost the eye pigmentation. The pigmentation is present in the tioglo- bites cocytus and giaquintoi. Obviously a need exists for the retention of eye pigment in the soil and animal-burrow species so that they can detect light, and avoid it. This need for retention of the optic pig- ment has obviously decreased for the troglobites. In the troglobitic Ptomaphagus the eyes have not been fully lost. None of them is, strictly speaking, eyeless. However, those that have none of the optic pigment neces- sary for insect vision can certainly be called blind. Blindness will also result with neural degeneration of the optic tract. The head of the troglobite P. hirtus of Mam- moth Cave was examined by Packard (1888: 116) and no optic ganglia or optic nerves were found. This lack of neural connection between the brain and the eye rudiment can be assumed for the other troglobitic species of the southeastern United States. As indicated, all the tioglobitic Adelops possess eye rudiments. This contrasts strongly with the bathysciines, with the great majority of the 581 Eurasian species being completely anophthalmic. This is a rule in western Europe, but a few eastern European species possess eye vestiges or rudiments. The least reduced of all bathy- sciine eyes is found in Adelopsella hosnica, which is comparable in body size to P. hirtus. There are about ten pigmented facets in the eye. The size of these eyes, the least reduced in all the bathysciines, is that of the most re

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• bookauthorharvarduniversity
• bookcentury1900
• booksubjectzoology