Whereas monarch caterpillars have two pairs of tentacles, queen caterpillars have three pairs: two longer tentacles toward the front, and a shorter pair near the rear.
Black swallowtail caterpillars have stout green bodies with black and yellow stripes; the stripes can also have yellow dots on top.
These caterpillars have tan faces and slender brown bodies with a pair of longitudinal yellow stripes edged in black.
The brown hooded owlet caterpillar has a glossy black head and body; a wide orange stripe centered between black, white, and yellow pinstripes that run down the back; short yellow and white lines on the sides; and a horizontal red line along the bottom by its legs.
You can probably guess by its name that this caterpillar can be identified by its zebra-like black-and-white pattern along its body.