Nice find! These are not commonly encountered. This looks like a looks like Spotted-winged Antlion (Dendroleon obsoletus), a native insect found throughout Maryland. The link on that gallery page to the BugGuide database entry provides a few details about their life cycle.
This work is supported in part by New Technologies for Ag Extension grant no. 2020-41595-30123 from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.