Tag Archives: tracheal system

You never know what you might discover by looking at a plant. For example, while I was waiting for someone I looked at a shrub in front of a store. I saw signs of caterpillars, so I looked closer.

This leaf was rolled up. It looked suspicious. I decided to take a look inside.

There was a small green caterpillar.

It turns out it wasn't the small green caterpillar I was expecting. The one I was expecting has a black head capsule. This one has a light-colored head capsule.

That warrants keeping an eye on it to see what it turns into. I put some leaves into a container with some moist paper towel.

Within a few days the caterpillar more than doubled in size. Its exoskeleton is so clear, you can see what it has been eating.

Let's look closer.

Can you see the white lines that look like tree branches? Those are the tubes that carry air (oxygen) into the caterpillar's body.

The tubes are called trachea and they originate at the round openings in the caterpillar's sides called spiracles. We usually can't see the trachea because the exoskeletons of most insects contain pigments that block our view.

This see-through caterpillar probably turns into a pyralid moth. With some luck, we'll find out what kind in the next few weeks.