The Catalpa Sphinx (Black and Yellow Worm)

The glow worm may attract the most attention when it comes to intrigue and beauty, but there is another type of “worm” that may attract attention for an altogether different reason. This worm is so odd looking, that one can’t help but wonder “what kind of worm is that?” That black and yellow worm dangling from a lone leaf or making its way up the trunk of a tree is commonly called a Catalpa Sphinx. Cool name for a cool worm, huh?

The Catalpa Sphinx is actually a common hawk or sphinx moth. It’s the larvae or caterpillar stage that you’re more likely to come across rather than the moth, which is dull and gray in color. The real name for the caterpillar of the Catalpa Sphinx is “Catawba Worm”or “Catalpa Worm.” The Catalpa Sphinx occurs in most southern states and throughout the eastern part of the United States. So if you live in any southern state or anywhere from Florida to New York and west to Iowa, Michigan, Kansas and Texas, chances are that bright “worm” you saw was a Catawba or Catalpa Worm.

UPDATE! All About Worms has partnered with HealthLabs so that
you can get tested for parasites at a fully-qualified lab near you,
no doctor's visit required
! Check it out at!

The Catawba Worm feeds on Catalpa trees. Its appetite is so great that this pretty pest can strip an entire tree of its leaves. This can be a serious problem for Catalpa trees that provide shade or nursery stock, and Catalpa trees that are popular for their ornamental beauty. The Catawba does not feed on any other tree outside of the Catalpa tree, so these trees are subject to attack at all times. The larvae are currently considered a threat to the survival of the Catalpa tree. Catalpa trees grow in all of the states mentioned above as well as in central and south central states such as Illinois and Indiana, and south to Arkansas and Tennessee.

The four life stages of the Catalpa Sphinx include the egg, larva, pupa, an adult. The larva (the worm) is white to pale yellow and it has a black spine and a horn on its rear. When the larva begins to develop, the colors change slightly. The head turns completely black and the body remains pale yellow in color but black markings develop all over the body. The pupa is reddish brown, and the moth, as mentioned earlier, is gray.

Because the Catalpa tree is considered a prized tree, known for its shading capabilities and its status as an ornamental tree, many people consider the Catawba to be destructive with no real value to the environment. Because of this, pesticides are commonly used to control infestations. In addition to human threats, the Catawba worm is constantly under attack by the wasp. The wasp is actually a parasite that deposits its eggs through the skin of the Catawba. The wasp larvae actually feed on the insides of the Catawba, and when the wasps are ready to leave the host, they spin silken cocoons on the Catawba’s skin. An infected Catawba does not survive into adulthood.

No Paywall Here!
All About Worms is and always has been a free resource. We don't hide our articles behind a paywall, or make you give us your email address, or restrict the number of articles you can read in a month if you don't give us money. That said, it does cost us money to pay our research authors, and to run and maintain the site, so if something you read here was helpful or useful, won't you consider donating something to help keep All About Worms free?
Click for amount options
Other Amount:
What info did we provide for you today?:

While many would say the Catawba worm is a pest, most fishermen would disagree. Catawba or Catalpa worms are extremely popular for fish bait.

Leave a Comment (but to submit a question please use the "Submit a Question" link above; we can't respond to questions posted as a comment)

Menu / Search

All About Worms