Bugs and Bug-like Things, Part 1

When I take people on nature walks, especially ones that emphasize wildflowers and their invertebrate visitors, I'm often torn as to what names to give things.  Sticking strictly to the "scientific" or "technical" names for bugs and bug-like things would be foolish unless I had a lot of guests with strong biology backgrounds.  In that case, I'd learn as much or more from them as I would teach.  The matter can be complicated by the fact that the "common" or "popular" names for things vary regionally and the same bug might have half a dozen or more names over its range.  A good example of this would be the bug known by scientists as Stenopelmatus fuscus.  It's know by common names such as Jerusalem Cricket, Potato Bug, and Nina de la Terra, among others. 
In my collegiate dictionary, there are 8 definitions for "bug."  In the most general sense, a bug could be any small invertebrate with legs, including insects, spiders, centipedes, snails, or in some cases even legless things like worms.  In a slightly more restrictive sense, the word "bug" might refer only to Arthropods - insects, spiders, centipedes, millipedes, etc., but not worms or snails.  In a still more restrictive sense, "bug" might be synonymous with "insect." 
So, let's talk "insects."  If these are taken to me the biological Class Insecta, that would include invertebrates (no backbone) with segmented bodies and three pairs of legs, and usually one or two sets of wings.  In biological nomenclature a Class is divided into Orders, and orders into Families. 
Of the critters pictured above, the top photo is of a spider, a Western Lynx Spider, which is in Class Arachnida, so it's not an insect, but it might sometimes be considered a bug in the general sense.  The remaining photos are of Insects.  Photos number 2 and 3 are of butterflies and number 4 is a moth.  Many people would peg numbers 2 and 4 as butterflies because they are colorful and number 3 as a moth because it's white and fuzzy.  The easiest way to tell moths from butterflies is to look at their antennae.  If they don't stop and sit still for a while, that can be difficult.  Butterfly antennae are thin rods with little bulbs at the tips while moth antennae are feathery or fern-like.  Many moths fly mostly or entirely at night, but the Red-shouldered Ctenucha Moth in photo #4 flies in broad daylight.  The first time I saw one of these from a distance, it was quite restless and wouldn't let me get close.  I mistook it for a wasp!  Anyway, butterflies and moths are grouped together in the Order Lepidoptera, one of some thirty orders of insects.  The Jerusalem Cricket mentioned above, but not pictured, is in the Order Orthoptera along with grasshoppers, katydids, praying mantises, and cockroaches.
Now, we'll move on to "true bugs" and beetles in the next post.