You cannot see the dots without the help of a strong microscope, but they are there.
These little dots are sensitive spots. There is a nerve coming from the insect's brain to each dot.
Some of the dots are sensitive to odors, just as the nerves of our nose are sensitive to odors.
May thinks it is very funny that the insects smell with antennæ instead of with noses.
The insects, no doubt, would think it very funny for us to smell with, noses instead of with antennæ, if they thought about it at all.
The little dots on the antennæ are extremely sensitive to smells. They are often much more sensitive than our noses.
Put a bit of food at some distance from a hungry cockroach, and it will not be long before a pair of long, sensitive feelers will come waving to and fro out of some dark corner.
Little Mrs. Cockroach has smelled the dainty morsel, and, as soon as it is dark, out she will run, her feelers moving eagerly this way and that, until she has found it.
Yes, May, insects also feel with their antennæ. That is why the antennæ are often called "feelers."