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“Inasmuch as we now have a cursory knowledge of the movements made by each individual leg for itself,—movements, however, which plainly occur very differently according to the structure of these appendages,—the question now is of the combined play, the total effect of all the legs taken together, and therefore of the walk and measure of the united work of the foot.

“In opposition to the caterpillars and many other crawling animals which extend their legs in pairs and really swing them by the worm-like mode of contraction of the dermo-muscular tube, the legs of fully grown insects are moved in the contrary direction and in no sense in pairs, but alternately—or, more strictly speaking, in a diagonal direction.

“For an examination of the gait of insects, we choose, for obvious reasons, those which have very long legs and which at the same time are slow walkers.

“Insects may be called ‘double-three-footed,’ from the manner in which they alternately place their legs. There are always three legs set in motion at the same time, or nearly so, while in the meantime the remaining legs support the body, after which they change places.