I noticed something interesting in the book of Leviticus last night. Here is
Leviticus 11:20-23
as it appears in the New Revised Standard Version:
20All winged insects that walk upon all fours are detestable to you.
21But among the winged insects that walk on all
fours you may eat those that have jointed legs above their feet, with
which to leap on the ground.
22Of them you may eat: the locust according to its
kind, the bald locust according to its kind, the cricket according to
its kind, and the grasshopper according to its kind.
23But all other winged insects that have four feet are detestable to you.
There are no winged insects that "walk upon all fours." Insects, by definition, have six legs. The author may not have been using our modern scientific definition of "insects" (and probably wasn't), but there are no similar creepy-crawly things that have four legs either. Spiders and scorpions have eight. Centipedes, millipedes, and isopods have more.
Some people attempt to address this apparent contradiction between the Bible and nature by claiming that the back legs of the locusts, crickets, and grasshoppers don't count as legs, because they're used for leaping, not walking. But I think this misses the point. If these insects are exempt because they jump with their back legs and walk with their front two legs, what about all the insects that
don't jump? What about cockroaches? (Yes, some cockroaches can fly. I'm sorry to break this to you if you didn't already know.)
If one defines "winged insects that walk upon all fours" as "winged insects that walk upon all fours in the sense that they use their back legs for jumping," then the "winged insects that walk upon all fours" are the same as "those that have jointed legs above their feet, with which to leap on the ground." It's like defining fruit as apples, pears, and cherries, and then saying, "You can't eat any fruit, except apples, pears, and cherries."
Furthermore, and perhaps this is a translation issue, but note the bit about "those that have jointed legs above their feet." In this case, the back legs are being included in the feet tally. But verse 23 specifically says, "all other winged insects that have four
feet are detestable to you" (emphasis mine). Even if one argues that the back legs of jumping insects shouldn't be counted as legs because they're used for jumping, their feet are still feet.