The bulk of the images here are of the braconid cocoon clusters that are often found near (if not attached to) the caterpillars from which the wasp larvae have emerged.
Solitary ichneumonoid cocoons have been a source of much confusion, because it is often believed that the braconid genus Meteorus is the only wasp that makes a cocoon suspended by a thread. Most such cocoons that have been submitted to BugGuide are actually made by ichneumonids. The one below is a confirmed Meteorus, with the adult that emerged shown at right.
The following cocoon, although very different from the one above, is almost identical to the one on page 23 of Wagner (1)
that is identified as Meteorus
...However, see this comment on the above images from Dr. Scott Shaw, University of Wyoming:
"The upper three images, with the cocoon suspended from a grass blade, are indeed a Meteorus species. The adult shown is a male, so I will not hazard to guess the species. Identification to species would require a female specimen for examination.
"Your suspicion is correct, the lower cocoon is not a braconid. The lower photo, with the more oval cocoon with a lateral band is Ichneumonidae, from the subfamily Campopleginae. It is definitely not Meteorus... Your website link mentions that this cocoon image is similar to one identified as Meteorus in a publication by Wagner. I did not follow up on that, but I’m copying this correspondence to Dave Wagner, just in case it was not identified correctly. This one at least is definitely a campoplegine ichneumonid."
Askew (1971) mentions Meteorus as one of a few braconid genera that have cocoons suspended from vegetation by long, silken cords (along with the ichneumonid Charops), but does not name the other genera.
Askew, R. R. 1971. Parasitic Insects. American Elsevier Publishing Company, Inc., New York. (2)