On segment VIII the postero-lateral corners are often armed with points or teeth and these may form a contiguous comb (Cb), which may surmount a cuticular projection or spur (115d.jpg). They are used to push the pupa along its tube.
CbB - breadth of comb
CbL - length of comb

Alternative forms for comb of segment VIII : Cb, CbB, CbL.