Penis
Domestic cats have barbed penises, with about 120–150 one millimeter long backwards-pointing spines. Upon withdrawal of the penis, the spines rake the walls of the female's vagina, which is a trigger for ovulation. Lions also have barbed penises. Male felids urinate backwards by curving the tip of the glans penis backward. When male cheetahs urine-mark their territories, they stand one meter away from a tree or rock surface with the tail raised, pointing the penis either horizontally backward or 60° upward.
Megaphragma mymaripenne
Uniquely, by the time "M. mymaripenne" reaches adulthood, 95% of its nervous cells have lost their nuclei. Only 339–372 nuclei are found throughout the central nervous system, of which 179–253 are found in the brain. The nervous system of the pupae of "M. mymaripenne" makes up 19% of its body mass, 11% of which is the brain. Unlike in adults, cells in the pupae have nuclei. Only in the final stage of development do these undergo lysis, which greatly reduces the volume of the nervous system. While the brains of pupae are 93,600 μm, those of the adults are only 52,200 μm. Accompanying this shrinkage of brain volume is a shrinking of the occipital area of the head, with the cuticle folding into helical spirals.