Official descriptions of species and other taxonomic groups include what’s called an etymology section. That is, an explanation of the name chosen by the author. Originally these names were mostly supposed to be descriptive, like Phyllidia polkadotsa. Sometimes the names refer to a place, like Helobdella nununununojensis (from a Quechua placename Ñuñuñuñuñoj). They can also honor people, like the beautiful species Chtonobdella tanae (named for Amy Tan):
Centipedes and millipedes are in their respective taxonomic classes, Diplopoda and Chilopoda. Together they are in the subphylum Myriapoda. Each of these official scientific names is a reference to Greek words for certain “numbers of feet” (poda). The common-names, centipede and millipede, are references to numbers of feet as well. Oddly, those common-names are from Latin, not from Greek. Odder yet: they are not the same numbers – not even close.
There are no millipedes
The name “millipede” derives from the Latin “mille” for 1000 (not a million) and “pedes” for feet. No millipede even comes close to a thousand feet. Narceus americanus, the common millipede in Eastern North America has only 182 feet.
The largest millipede is the African species Archispirostreptus gigas that grows to more than a foot in length. Even this monstrously massive millipede has a scant 256 feet.
The rarely seen Californian Illacme plenipes boasts upwards of 185 body segments each with 2 pairs of legs. Still, 740 falls well-short of the the Latinate expectation for 1000 legs, never mind the tiny (3 millimeter) duff millipedes tallying 26 in all. Which is to say, at most, millipedes are centipedal.
Everything is a centipede
For centipedes the common name also is Latin – “centum” for 100, and “pedes” for feet. The common house centipede, Scutigera coleoptrata, with only 13 pairs of feet is more decipedal than centipedal. Don’t kill them. They are probably busy keeping down the number of spiders, bed bugs, termites, cockroaches, and silverfish in your home.
Many centipedes do approximate the centipedal condition. They range from species with fewer than 10 pairs of legs to others exceeding 150 pairs. What is certain, however, is that no centipede is exactly centipedal. Centipede species have odd numbers of body segments. Each segment has one pair of legs instead of the two in millipedes. The longest centipede, the Amazonian Scolopendra gigantea, sports 23 pairs. Regardless, no centipede can have exactly 50 pairs, and thus no centipede can actually be precisely a centipede.
Still, the common-name “centipede” makes more sense than their class name, Chilopoda. The “chilo” in “Chilopoda” is from the Greek word for 1000, not 100. It is the same Greek word you know from “kilo”-meter – 1000 metres. If millipedes aren’t chilo-podous, centipedes do not measure up either. A centipede fitted with a thousand feet, is an order of magnitude greater of an exaggeration than is any thousand-feeted millipede.
The name of the song is called “HADDOCKS’ EYES.”’
Through the Looking Glass – Lewis Carroll
‘Oh, that’s the name of the song, is it?’ Alice said, trying to feel interested.
‘No, you don’t understand,’ the Knight said, looking a little vexed. ‘That’s what the name is CALLED. The name really IS “THE AGED AGED MAN.”’
‘Then I ought to have said “That’s what the SONG is called”?’ Alice corrected herself.
‘No, you oughtn’t: that’s quite another thing! The SONG is called “WAYS AND MEANS”: but that’s only what it’s CALLED, you know!’
‘Well, what IS the song, then?’ said Alice, who was by this time completely bewildered.
‘I was coming to that,’ the Knight said. ‘The song really IS “A-SITTING ON A GATE”: and the tune’s my own invention.’
Confusingly, the class name for millipedes is Diplopoda from the Greek for “2 feet.” Of course, no millipede has 2 feet. You are a biped. The “diplo” refers to the number of pairs of feet in each segment (2 pairs). The actual number of feet in each segment is 4, not 2, but Tetrapoda was taken by 4-legged animals, like cows. Tetrapoda also includes you, even if you are bipedal.
Chilopoda and Diplopoda are classes in the subphylum Myriapoda. This is, perhaps, the greatest exaggeration of all. The Greek word “myriad” is for 10,000. Like the kilometre, myriametre used to see usage. I suspect only in very long countries. Norway is about 38 myriameters long. Myriametre may have fallen out of favor, but “myriad” is on the upswing. It generally now means some unspecified large number.
In other words, a word for a very precise number has come to mean “imprecisely innumerable.” As well, the manners of its use – “myriad ways,” “a myriad ways,” “a myriad of ways” – are myriad.
What’s in a name?
There are myriad toxins in centipedes and millipedes. Moreover, the differences epitomize the distinction between “venomous” and “poisonous”. So knowing the difference, with but a word, can mean the world.
Centipedes can deliver a venomous assault with a pair of modified legs mounted next to their mouths. Because the venom glands are attached to legs, technically it is a sting, not a bite. This is a distinction without a difference in terms of pain. Present in the venomous mix are nasty enzymes and a painful dose of serotonin. Something also in venoms of bees, wasps and stingrays.
What usually begins with an immediate burning pain, progresses locally to a deep torn-muscle radiating “sprain” sensation. Only a single death has been attributed to a scolopendrid centipede sting. That 7-year-old Filipina suffered a rare allergic response, implying that she had been stung at least once previously.
Millipedes don’t sting. They can make up for this with enough toxicity to ward off most predators. Many defend themselves with strong skin irritants like cresols, phenols and benzoquinones. This is so effective that South American woodcreepers preen with millipedes in a behavior called “anting” in order to reduce louse infestations on their feathers.
In the Pacific Northwest, Harpaphe haydeniana produces prodigious quantities of cyanide when it feels threatened. Most millipedes make cyanide. But typically there is more cyanide in cassava than there is in your average millipede. Use a leaf to safely pick them up and admire.
Give them a whiff. There should be a distinct note of almonds.
Postscript:
By a year-and-a-half my daughter was playing with leeches. I’d watch carefully so they wouldn’t be allowed to bite as she let them crawl across her palm and up her arm. She’d eagerly reach into a pail of maybe 30 black and orange leeches all swimming avidly and inching their way up the sides looking for a meal. To her they were smooth and cool to the touch, not slimy or in any sense creepy. This convinced me that fears of leeches, spiders or snakes, for example, must be learned behaviors, not instinctual ones. Such revulsions must be instilled by panicked parents… or so I thought.
That winter, when she was 17 months old, I had taken to opening each card we received bearing holiday wishes with her so that she could marvel at the pretty colors, the snowmen, the snowflakes and the reindeer. There was one from a well-wishing student, however, that challenged my notions about fear. I opened the envelope to reveal a red card with curvacious, black, 4-inch, anatomically accurate, latex centipede model fixed to the front.
As a shudder ran through her tiny frame and the color left her face, I knew that the humorous intent was completely lost on my daughter. But I had to be sure, so I hid the card only to reveal it again a few minutes later – same creeped-out reaction. Scientifically (but risking Child Services being called on me) I repeated this several more times. These were bona-fide heebie-jeebies (interestingly a noun without equivalent that has its origins in a human-sacrificial ritualistic dance). My daughter had not yet seen a real centipede, and in the short time she’d been alive, no one had taught her to fear them. This was instinct! Whether it was something about the shape, or unexpectedly large number of legs, I didn’t know. Still don’t. She’s okay with them now.