This was no wee cat - the tubular beast was a few inches long, although it blended well with the sandy substrate. It, like most caterpillars, was also an eating machine. Note the fresh piles of frass - caterpillar scat - near its rear (left). I wonder if that frass might be the chewed remnants of the rough buttonweed depicted earlier. The buttonweed, or at least similar species in the same family, are known host plants for this species.
Anyway, it took little time to determine its identification once books were accessed: Tersa Sphinx, Xylophanes tersa. Small wonder none of us had seen one. This is a largely tropical moth, typically occurring from the southern U.S. south as far as Argentina.
Tersa Sphinx moths are well known for their migrations, which can bring small numbers far north of the usual range. Very small numbers appear in Ohio most years, but I did not think they were known to reproduce here. Obviously, based on our caterpillar find, they at least attempt to. I posted a photo of the caterpillar on Facebook, which prompted a few interesting responses. Bob Placier reported seeing a caterpillar in Hocking County a few years ago. And Sherri Werdebaugh encountered a few caterpillars in NW Ohio several years ago, but had reason to believe that they might have been imported on nursery stock.
In the case of our find, I wouldn't think there'd be any question that a free-flying moth deposited the eggs that led to this caterpillar.
Winged insects are proving to be hyper-responders to warming mean annual temperatures, with an ever-increasing cast of southern butterflies and dragonflies leading the charge. Southern and even tropical species are appearing far to the north of their "normal" ranges with increased frequency, or so it would seem. One might predict that this beautiful sphinx moth will become a regular part of Ohio's Lepidoptera before long.