. British insects : a familiar description of the form, structure, habits, and transformations of insects. agoified. are developed in the tarsus, and the claws are generallywanting. Fig. 11 is the hind leg of the little shinyhlack whirli-gig beetle, also a denizen of the waters, where it is ren-dered conspicuous by the marvellous rapidity of its evolu-tions. The wonderful little living paddles by which thesemotions are made deserve close attention, and far exceedin beauty the oars of the Notonecta. They are quite flat,the femur, tibia, and joints of the tarsus being composedof horny plates bea
. British insects : a familiar description of the form, structure, habits, and transformations of insects. agoified. are developed in the tarsus, and the claws are generallywanting. Fig. 11 is the hind leg of the little shinyhlack whirli-gig beetle, also a denizen of the waters, where it is ren-dered conspicuous by the marvellous rapidity of its evolu-tions. The wonderful little living paddles by which thesemotions are made deserve close attention, and far exceedin beauty the oars of the Notonecta. They are quite flat,the femur, tibia, and joints of the tarsus being composedof horny plates beautifully articulated together. The femurand tibia are triangular. The three upper joints ofthe taisi are excessively dilated on the inner side, sothat when expanded they form, with the crescent-shapedfourth and fifth joints, a thin semicircular disk. Thelimb in this state opposes to the water these broad flathorny plates. When contracted (fig. 12), the tarsal jointsfold over each other like the vanes of a fan, and mayconsequently be drawn through the water with little EXTERNAL STRUCTURE OF INSECTS. 37. resistance. The limb is, like most swimming legs,beautifully fringed with hairs. In figure 13 is seen a leg fitted for leaping, the leg ofthe common grasshopper ; and the thick and muscularthigh, the strong butslender and spurred tibia,and the firmly knit butsupple joints, all pointto the action for whichthis limb is this, the greatlength of the hind orleaping legs as com-pared with the two otherpairs should be remem-bered,and the leaping legof the grasshopper willbe seen to be as good an example of peculiar development for a special purposeas the swimming legs lately described. From this we turn to the fore leg of a near relation ofthe Grasshopper, but an insect of far other habit=Figure 14 represents the burrow-ing mole-like hand of the molecricket. In this curious instru-ment, as in the paddle of thegyriuus, the tibia and tarsus areunusually broad and flat, and
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Keywords: ., bookauthorme, bookcentury1800, bookdecade1870, booksubjectinsects
