Oxygen will travel directly to where it is needed and pass into the tissue. The only goal in life for an adult butterfly is to reproduce. The males look for females to inseminate. The females lay eggs. Within the males' abdomen are the sperm producing organs.
Butterflies mate facing in opposite directions with their abdomens attached.
The penis enters the female at the same location where the eggs come out. When the male ejaculates, the semen enters a small storage pouch inside the females abdomen. After mating, the female has about 100 eggs inside her and a pouch full of the male spermatozoa. Once gravid, she will perform a kind of self-fertilization. When she places an egg on the hostplant, as the egg is passing out of her ovipositor, it will pass this pouch.