Cockroach with ootheca
Mother cockroaches commonly lay their eggs within oothecae, an elongated protective structure such as the one seen extending from the abdomenn in this female Periplaneta fuliginosa. Researchers in China recently discovered the oldest known cockroach fossils with oothecae, at 125 million years old. (Photo credit: Toby Hudson/Wikimedia Commons, CC BY-SA 3.0)