University of Kentucky Department of Entomology

Mystery Bug Answers

Mystery Picture #64

Mystery Picture #64

R. Bessin, University of Kentucky
R. Bessin, University of Kentucky
(Mystery Pictures)(Mystery Pictures)


Woollybear Caterpillars (or "woollyworms" as they are called in parts of Kentucky!) are most often noticed in the fall as they travel across the ground, looking for a good place to spend the winter under fallen leaves and plant debris. Many people claim the pattern of their stripes predicts how long and how cold the winter weather will be.

JUST FOR FUN: Do you know how to "read" the stripes? What kind of winter does this little fellow predict?

ANSWER: According to convention, the brown stripes indicate warm spells or thaws and the black stripes indicate cooolllld weather! So, reading from head to tail, this little caterpillar is predicting a fairly long cold start to the winter, followed by a nice long January thaw, then a short return to cold weather before spring.

Do they really predict the winter? It seems that way because we see different patterns in different years, but actually there are eight or so different species of woollybear moths. Each species has a different pattern ranging from all brown to all black, but within each species all the caterpillars have the same pattern. So if you see caterpillars with different patterns, you are seeing more than one species of woollybear moth caterpillar!


This small wasp looks dangerous, but is actually quite harmless to humans. It is called an Ichneumonid Wasp. This is a beneficial wasp--its larvae are parasites of harmful caterpillars that attack the stems and leaves of plants. Some species of this group of wasps can even detect wood-boring beetle larvae through the thick bark of trees and inject their eggs into them.

EXTRA CREDIT: What is the function of the long structure projecting from the back of this wasp?

ANSWER: This is a picture of a female ichneumonid wasp and the long structure is her ovipositor inside its protective sheath. Once she locates a prey organism (a caterpillar or beetle larva within a stem or under bark, for example) she uses the sheath to drill a hole into the plant material then extends her delicate ovipositor to the prey where she lays an egg. When the egg hatches, the wasp larva will attack and feed on the caterpillar or beetle larva, eventually killing it.

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