the GNU version of the Collaborative International Dictionary of English
n. The larva of any geometrid moth, as the cankerworm; a geometer; a measuring worm.
The Century Dictionary and Cyclopedia
n. In entomology, a looper, measurer, or measuring-worm; the Iarva of any geometrid moth. See measuring-worm, inchworm, looper, loopworm, and especially geometer, 3. See cuts under cankerworm and Cidaria.
Word Usage
"Other bugs to look out for this spring include the elm bark beetle and the elm spanworm."