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Fig. 3. Attempted jump by a restrained Aphrophora viewed ventrally. All
the legs are free to move but make no contact with any substrate. (A) Images
captured at 1000 s-1 and with an exposure time of 0.5 ms, are
arranged in three columns. Between frames -2110 and -2000 ms, the right hind
leg is gradually swung anteriorly by a levation of the trochanter about the
coxa. The femur now obscures the lateral protrusion of the coxa. The leg
remains in this levated and cocked position for 2 s with no changes in the
angles of coxo-trochanteral joint or other more distal joints. Toward the end
of this period (between frames -2000 and -1 ms), the coxa moves forward about
the thorax, indicated by the reduction in distance between its anterior edge
and the posterior edge of the coxa of a middle leg (yellow horizontal lines).
The joint between the trochanter and the coxa then depresses rapidly so that
within 1 ms the whole leg has been extended (frames -1 ms and 0 ms). (B) Plot
of the angular changes of the coxo-trochanteral and trochantero-femoral joints
of the hind leg during the whole sequence. The vertical yellow bars indicate
when the hind legs achieved their fully cocked position (left) and when the
jump occurred (right).
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