Bugs, True Bugs and Beetles

I thought I'd give my milkweed spot one more try and see if I could find a Red Milkweed Beetle. No beetles, but I did find some of their recently-laid eggs on the undersides of quite a few leaves. I did, however, find a Small Milkweed Bug, Lygaeus kalmii, on a rapidly browning Showy Milkweed, Asclepias speciosa. In a nearby neighborhood, I found some Gumplant, Grindelia nana, with and insect guest, either a bee or a fly mimicking a bee.
I thought I'd take this opportunity to ramble on about some interesting terminology and naming conventions. The word "bug" is used in many ways, and the two insects pictured here fit the category as it's generally used, namely any sort of multiple-legged invertebrate. When applied loosely, the word bug can refer to all insects, spiders, centipedes, and scorpions. Even snails and slugs when used extremely loosely. Insects, of course, and invertebrates characterized by having 6 legs, although it can get more complicated than that, especially when you're viewing larval stages. So, for the moment, let's agree that both critters pictured above are insects, and may also be called bugs. The insects, in a biological category named Class Insecta, are divided into numerous groups (20 - 30+) called Orders. One order, Order Coleoptera, includes the insects we call beetles. Another, Order Orthoptera, includes grasshoppers and crickets. Finially, there is an order of insects called Hemiptera whose common name is "true bugs." It so happens that the Small Milkweed Bug pictured above belongs to that order, so it is a true bug. The third photo includes an insect that is either a bee or a fly that mimics bees. I'll need to search further in my field guides to identify it. An entomologist would spot the type instantly. Anyway, if it is a fly of some kind, it's in the Order Diptera, but, if it's a bee, it's in the Order Hymenoptera.
A couple other tidbits are in order here. The orders of insects end in the suffix -ptera which means wings. So, the broad divisions of the insects into orders is based mostly on characteristics of the wings. Interestingly, the same suffix is used in the name of the mammalian order that includes the bats, Order Chiroptera. The last tidbit: when I name a general category such as milkweed or beetle, I begin the word with a lower case letter, but when I name a specific type or species, such as the Red Milkweed Beetle, or the Small Milkweed Bug, I capitalize. That's the convention in most, but not all field guides. The scientific name of genus and species, together known as a binomial, are italicized with the generic name capitalized and the specific epithet beginning with lower case.
It's been quite a while since I posted such an extensive biology lesson here - you could have just looked at the pictures, there will not be a quiz - so I'm glad I got it out of my system! Happy "bug" hunting.