The jaws, moreover, of the working ants of the several sizes differed wonderfully in shape, and in the form and number of the teeth.

But the important fact for us is that, though the workers can be grouped into castes of different sizes, yet they graduate insensibly into each other, as does the widely-different structure of their jaws.

I speak confidently on this latter point, as Sir J.

Lubbock made drawings for me, with the camera lucida, of the jaws which I dissected from the workers of the several sizes.