In August, I photographed several of these pretty little 'caterpillars' while walking in a beautiful New Hampshire woods.  Later I tried to identify them, and I combed through my caterpillar guide (Caterpillars of Eastern North America, by David Wagner), various butterfly guides, searched the internet for "hairless, yellow and black speckled caterpillar" and came up with nothing.  But the other day, a colleague emailed me a link to another photographer/insect enthusiast's website http://lexingtonalive.net/ photographs by Ned Eisner). I looked at just about all of his insect photos and happened upon a larva that looked a lot like my "caterpillar".  Turns out my guys are not caterpillars, (which is what butterfly and moth larvae are called), but are the larvae of a type of "Pine Sawfly".  (And if you are wondering how to tell the difference between caterpillars and pine sawfly larvae, you will easily find the answer on line.) These little larvae eat pine needles and given enough of them, they can defoliate a pine tree in no time.  Next, I looked for an image of the adult "sawfly" and I learned something else: that they aren't flies at all.  They are related to wasps and bees and belong to the same order, Hymenoptera.  And according to Wikipedia they've been around for millions of years.  All this new information is quite fun and exciting.  Who said ignorance is bliss?  The bliss is in the learning!