Phaeoura quernaria - Hodges#6763 (Oak Beauty) - imm.
Photo: 04/17/16, noon.

The larvae of the Oak Beauty feed on leaves of a variety of deciduous trees including birch, cherry, elm, hawthorn, oak, poplar, and willow. Their body is short and stout for a geometrid caterpillar mottled with browns and grays. Each spot on the head is made of ten to 20 speckles and the body has raised warts on the second and eighth abdominal segments and ventral warts on the third.  

bug guide (these photos):