catalpa worms?

Question

in my area catalpa worms show up on trees around the first of july. where exactly do they come from. are the eggs in the ground or are they on the tree leaves.

Answer 1

The pupa overwinter underground,adults emerge in spring and then lay their eggs on the catalpa, when they hatch the caterpillar then emerges starts to feed and when it is full grown it burrows into the soil and the cycle starts again.
For more detailed info. refer to this site : http://www.ag.auburn.edu/enpl/bulletins/catalpasphinx/catalpasphinx.htm