Possibly Wasp Pupae

Subject: some sort of pupae? larvae?
Location: Missouri, United States
April 1, 2015 11:34 pm
found these while digging out at our pond. I suspect they were underground and I dug them up. I picked them out of the water and returned back to the house to investigate them.
P.S. if you’re wondering why I’m digging the pond, it dried up and now has a hard time staying full of water. if I don’t dig it, the tadpoles can’t mature! 🙁
Signature: Michael

Possibly Horse Fly Puparia
Possibly Horse Fly Puparia

Dear Michael,
We are guessing that these might be the Puparia of Horse Flies.  Many Horse Flies have aquatic larvae.  According to BugGuide:  “larvae found in streams, ponds, and marshes, especially along the edges and in the sea shore.”
  Flies have an interesting metamorphosis process, and the pupa is encased in a puparium.  Though the information is about Blow Flies, the USA.Gov Visible Proofs Forensic Views of the Body page states:  “The larvae becomes shorter and stouter and the outer cuticle (skin layer) of the larvae hardens into the puparium and slowly darkens over a period of about 10 hours.”  We have several images of Horse Fly larvae on our site, and we cannot locate matching images to substantiate our guess at this time, but we are going to seek a second opinion.

Horse Fly Puparia, we believe
Horse Fly Puparia, we believe

Eric Eaton Responds
Hi, Daniel:
Don’t think they are horse fly puparia.  Almost remind me more of wasp larvae inside….How long has the pond been dry?

Thanks Eric,
Good question. I will write back and ask.  You think a wasp that digs a hole as a nest?

There are hundreds of species of solitary wasps that dig burrows for nests.  If the puparia were large, I’m thinking cicada killer or horse guard.
author, Kaufman Field Guide to Insects of North America

Michael provides additional information
it’s certainly possible they could be wasps, the pond has been dry since late last year and only recently started filling up from the rains this year. I wonder what sort of wasp though, very interesting.

unfortunately I cannot, I already threw them away. but I’d say the biggest was about the length of a nickel if that helps at all.

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