. Transactions of the Entomological Society of London. wards. Some Mallophaga resemble Poly-ctenidae in possessing single long bristles on the tibiae ( 26-29). The claws at the end of the tarsi appear to be organs whichaxe easily modified. The claws of the fore-tarsi are oftendifferent from those of the other tarsi in Ectoparasites, as is ( cl ) also frequently the case in other insects. We have not noticedany special sexual adaptation of the claws in Epizoa, but thetarsi have often a different covering of bristles in the sexes. There is a single claw in some mammalian Mallophaga
. Transactions of the Entomological Society of London. wards. Some Mallophaga resemble Poly-ctenidae in possessing single long bristles on the tibiae ( 26-29). The claws at the end of the tarsi appear to be organs whichaxe easily modified. The claws of the fore-tarsi are oftendifferent from those of the other tarsi in Ectoparasites, as is ( cl ) also frequently the case in other insects. We have not noticedany special sexual adaptation of the claws in Epizoa, but thetarsi have often a different covering of bristles in the sexes. There is a single claw in some mammalian Mallophaga andin the Anoplura (text-figs. 16 and 17). This claw is soconstructed that the insect can take a firm hold of a hair ofthe host. It is singular that this kind of claw should be foundonly in those two groups, which are usually placed far apartin the system. If there is really no relationship between theAnoplura and mammalian Mallophaga, the close agreementin the claws is certainly most remarkable. All the other Epizoic insects have double claws of the. Fig. 16. Tarsus of Pediculus humanus L. (1758).,, 17. ,, ,, Trichodectes caprae Gwilt (1843).„ 18. ,, ,, Ancistrona vagelli Fabr. (1787).,, 19. ,, „ Adroctenes horvathi Jord. (1911). sickle-shaped type usually found in insects (text-figs. 18and 19). In some groups (the majority of fleas) the clawshave a large basal tooth, in other cases they are quite simple,many intergradations occurring. Asymmetrical claws arefound in some genera of Polyctenidae (text-fig. 19) and ofCimicidae, the inner or posterior claw (i. e. posterior if theleg is stretched out at right angles to the body) being smallerthan the outer one. In this point the three groups of Ecto-parasites mentioned agree with the Rutelid beetles and the$ $ of the Agaristid genus Chelonomorpha, while in the butter-fly sub-family Acraeinae the opposite development has takenplace, the inner claw being the larger one. Among thePupipara also some slight asymmetry in the claws is
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