Question
We have a tree now we meed the wroms do you have any idea where we might buy them.  Mary

Answer
THE CATALPA SPHINX1 is a common hawk or sphinx moth, (Photo 1) but it is the caterpillar stage, (Photo 2), that is most often encountered and best known.   The caterpillars, commonly called catalpa worms or "catawba" worms, feed on leaves of catalpa and often completely strip trees of foliage.   Loss of foliage may be serious, especially for shade and ornamental trees and nursery stock.   While the catalpa worm is well known as a tree pest, it may be as well or better known to some for its attractiveness to fish.   The caterpillars have long been valued for fish bait, and references to their collection by fishermen date back at least to the 1870's when the species was first described . Here is one web site that says they carry live ones during the season you might contact them and see if they can be shipped when available.
http://catawbaworms.com/

The catalpa sphinx occurs throughout much of eastern United States from Florida to New York west to Michigan, Iowa, Kansas, and Texas .   It is generally most common in the southern states.   Catalpa is its only host plant, and all species of catalpa are apparently subject to attack.   Two native species, southern catalpa (Catalpa bignoniodes) and northern catalpa (C. speciosa), are common.  Southern catalpa tree is native to the southern states and occurs naturally along rivers and margins of swamps .   It is a medium-sized tree with broad crown, large leaves, and show white, purple-tinted flowers.   Northern catalpa is very similar to southern catalpa.   It occurs naturally as an occasional tree in some central and south-central states--Indiana, Illinois and south to Arkansas and Tennessee.    Both catalpas have been widely planted and have become established outside their natural habitats.

The catalpa sphinx overwinters as a pupa in the soil under or near trees infested the previous season.   In spring, pupae work their way to the soil surface and moths begin to emerge shortly after host trees have leafed out.   Time of moth emergence varies considerably by locality within the range and even from year to year in the same locality, depending on temperature and general weather conditions.   Spring moth activity can be expected in most years from about mid April into early May.   Moths mate and females lay eggs in masses on the undersurface of leaves.   Masses may contain 100-1000 eggs .   Eggs usually hatch in five to seven days  in normal years  hatch has usually occured and first-brood larvae are present by mid-May.   Newly hatched caterpillars feed as a group skeletonizing areas of leaf.   Later, larvae separate and feed singly, consuming whole leaves except for stubs of midribs and large veins.   Duration of the caterpillar stage varies but generally is about three weeks.   Full-grown caterpillars enter the soil and pupate.   New adults of summer generations emerge in about two weeks, but pupae of the last brood of the season overwinter in the soil and moths do not emerge until the following spring.  

I would check with a local live fish bait company (store) and ask if they carry live catalpa worms and buy some and put them on the trees. They should start eating the leaves and grow and spin a cocoon turn into moths and lay eggs. If this happens the you have gotten the caterpillars started on the tree. Do not pick them all off and you should be able to keep a population going.