Last evening after a very good downpour, I was in our backyard in Central PA and noticed this ? thumping his or her butt on the soft ground. It would thump and fly and thump and fly and then thump and wait. I believe it is depositing eggs but am not sure. I also am not sure what it is. Any help would be appreciated. Sincerely
Your insect is a Crane Fly in the family Tipulidae, and the behavior you describe is that of a female Crane Fly laying eggs. Female Crane Flies often oviposit in the ground, and the larvae, known as Leatherbacks, feed on detritus. For more on the life cycle of a Crane Fly, visit the Crane Flies of Pennsylvania website. We are not sure of the species but we will try to contact Dr. Chen Young to see if he can assist.
The image showed up okay this time and it looks like a female of Nephrotoma virescens to me. http://iz.carnegiemnh.org/cranefly/tipulinae.htm#Nephrotoma_virescens This species usually when freshly emerged are greenish in color and gradually turning greenish yellow as in this image. There is another species Nephrotoma alterna http://iz.carnegiemnh.org/cranefly/tipulinae.htm#Nephrotoma%20alterna which also has nice patterns on the top of the thorax. But I believe yours is a N. virescens. Thanks,