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Yesterday we talked a bit about about the human skeleton. Now let's compare it to an insect skeleton.

Insect and other arthropods have their supporting structure on the outside of their bodies. The outside skeleton is called an "exoskeleton." It has the same function as the vertebrate internal skeleton, that is protecting the internal organs and allowing for movement. The biggest difference is that the exoskeleton doesn't grow and must be shed or molted for an insect to increase in size.

When you first look at an insect anatomy diagram, it might seem like the vocabulary is unusual.

It turns out, however many of the parts are named the same as in humans.

For example, the name of the segments of the insect's legs correspond to the names of the bones in the human legs. The big bone in the thigh is the femur, the bone below the knee is the tibia, and the bones in the feet are called the tarsals and metatarsals.

A doctor of thoracic medicine specializes in the chest, particularly the lungs. A doctor might ask if you have a pain in the lower left abdomen.

The human jawbone is called a mandible, and insects with biting mouthparts have mandibles.

Insects have a membrane that helps them detect sounds called a tympanum. Humans have a tympanic membrane in the ear that helps with hearing.

Learning the vocabulary is easier once you see the similarities.

Can you find your femur? Can you see the large, jumping femur of this grasshopper?

We've been seeing a lot of bee flies in the genus Geron in our yard lately (link is to previous post).

Geron bee flies are more slender than most of their relatives and have a "humpbacked" appearance because their thorax bulges up in the back (dorsal surface).

 

As stated at BugGuide, the adults use their long, prominent proboscis to drink nectar from flowers. They seem to prefer sunflowers.

Because of their fuzzy bodies, they pick up pollen while feeding on nectar. When they carry the pollen to another flower, they help pollinate it.

So why were there so many of these flies on the palo verde tree this morning?

Looking closely, I noticed some caterpillars. Bee flies are parasites of other insects in general. Geron bee flies are parasites of caterpillars. These adults were probably looking for a caterpillar to lay their eggs on.

I'm going to spend some time watching the caterpillars to see if I can find out more. Look for an upcoming post about them.

Until then, do you have Geron bee flies in your yard? What flowers are they visiting?

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Back to the hollyhocks.

The light is so lovely on the white flowers.

Wait, what's that on the stem below the buds at the top?

It is a tiny praying mantis nymph.

Too cute.

Have you ever seen a newly-hatched praying mantis nymph?