Wasp
The largest social wasp is the Asian giant hornet, at up to in length. The various tarantula hawk wasps are of a similar size and can overpower a spider many times its own weight, and move it to its burrow, with a sting that is excruciatingly painful to humans. The solitary giant scoliid, "Megascolia procer", with a wingspan of 11.5 cm, has subspecies in Sumatra and Java; it is a parasitoid of the Atlas beetle "Chalcosoma atlas". The female giant ichneumon wasp "Megarhyssa macrurus" is long including its very long but slender ovipositor which is used for boring into wood and inserting eggs. The smallest wasps are solitary chalcid wasps in the family Mymaridae, including the world's smallest known insect, "Dicopomorpha echmepterygis" (139 micrometres long) and "Kikiki huna" with a body length of only 158 micrometres, the smallest known flying insect.
Hystrichopsylla schefferi
Hystrichopsylla schefferi, also known as the mountain beaver flea and giant mountain beaver flea, is a parasitic holarctic insect belonging to the order Siphonaptera, the "siphon-wingless" (fleas). The fully grown adult can measure as much as in length, and it is the largest living flea in the world. It is native to the American Northwest. Though most members of the genus "Hystrichopsylla" are not strongly associated with any particular host animal and will generally parasitize insectivores and rodents, "H. schefferi" is monoxenously associated with the mountain beaver with which its range is coterminous. The fleas of the family Hystrichopsyllidae, along with the family Pulicidae, are the oldest of fleas in evolutionary history. "H. schefferi" can be distinguished from the very similar and closely related species "Hystrichopsylla gigas dippiei" by the number of spines in the pronotal comb, as "H. g. dippiei" has 36 and "H. schefferi" has 46.