There are well over 3,300 species of Ichneumon wasps north of Mexico, making their identification difficult. Placing them in the family is more straightforward. Ichneumons have a lot of segments in their antennae and most have a broad white or yellow band on each antenna. Females, like the one in the picture, may wield a long, tail-like appendage. Although it looks threatening and reminiscent of a stinger, it is an organ for laying eggs. Of course, there are exceptions, some species have short ones that do function as stingers. Most ichneumon larvae are parasitic of moths and butterflies or sawfly larvae. Mothers lay their eggs on or in the insect host and the larvae develop and grow at the expense of it. Ultimately, the larvae kill the host. 
Photo by Pat Little on 6/1/20 in Missoula, MT