There are about 2,500 kinds of spiders on the North American continent north of Mexico, and thank goodness. Without spiders, we'd be overrun with insects.

It is estimated that each year the world's spiders eat enough insects to outweigh our entire human population. If you think about how many mosquitoes it would take to equal your own weight (about 200,000 mosquitoes per pound), perhaps you would be a little friendlier to spiders.

I like spiders and find them interesting even though they eat the insects that I also admire. Spiders are portrayed as monsters by writers of science fiction. While their appearance under a microscope is rather fearsome, there are only a very few that are dangerous.

Spiders have eight legs, whereas insects have just six. An insect's body is clearly divided into three parts: head, thorax and abdomen. It is impossible to tell where the head ends and the thorax begins. The spider has neither the antennae nor the compound faceted eyes of an insect, but it is well-equipped with its usual six or eight simple eyes. Attached to a spider's body in front of the legs are two palpi, or foot jaws, which grope and feel.

We think spiders, and webs naturally come to mind. The best time to see spider webs is early on a sunny morning when there is dew on the ground. The most remarkable webs are made by spiders that belong to the group called orb weavers.

Jim Gilbert's Nature Notes are heard on WCCO Radio at 7:15 a.m. Sundays. Gilbert is the author of five books on nature in Minnesota. He taught and worked as a naturalist for 50 years.