Mummy Wasp
This little wasp (only about 5 mm long, less than a quarter of an inch) was on our kitchen window on September 1, 2025. I was still getting used to the new camera at this point, so the pictures could have been better, but it will have to do.
In addition to its two quite large compound eyes, in the middle of its head are three fairly large ocelli (simple eyes) arranged in a triangle on a black spot. This is pretty characteristic of wasps, particularly the parasitic ichneumon and braconid wasps.
We can also see the wing shape and the pattern of spot and veins well enough to get a reasonable ID. This is most likely one of the “Mummy Wasps” in the genus Aleiodes, and looks a great deal like the ones in the circumscriptus/gastritor species group.
These are called mummy wasps because of the way that they kill their caterpillar hosts. They are “larval koinobiont endoparasitoids“, which means that (1) they parasitize insect larvae (in this case, caterpillars), (2) they wait until just before it pupates to kill their host, and (3) the parent injects her eggs directly into the caterpillar rather than laying them on its skin or near the caterpillar’s nest. So in the case of these wasps, they kill the caterpillar in such a way that it dries into a mummy, and then the wasps pupate inside of the mummified caterpillar.
In order to know which exact species of mummy wasp this was, I would have needed to see what kind of caterpillar it emerged from. They tend to specialize in a particular type of caterpillar, which depending on which species this is could have been tent caterpillars or armyworms. Both of those types of caterpillars are damaging pest species, so we can regard these wasps as being useful pest control.
Cool story about the name! Also, tent caterpillars are the worst. It serves them right for spinning those awful webs.
Such an intriguing little snapshot of nature 🐝! I love how this post highlights the fascinating world of mummy wasps — tiny parasitic braconid/ichneumon wasps that lay their eggs inside caterpillars and end up turning the host into a “mummy” as the wasps develop inside it. It’s a great reminder that even the tiniest insects have complex life cycles and play useful roles in controlling pest species like tent caterpillars and armyworms. Thanks for sharing such a cool close-up and giving us all a chance to appreciate an often-overlooked arthropod right at a kitchen window!