Species exhibiting mimicry increase in hot, humid latitudes and may be quite lacking in the temperate lands. The Amazonian species of Dasyllis Loew, which resembles bees of the group Eulaema and the various species of Diogmites Loew and Blepharepium Rondani, which resemble some species of wasps, may be considered examples of mimicry. The small asilid Megaphorus clausicella Macquart from the southern United States is a good mimic of Megachile bees. These examples are generally regarded as falling in the principle of synaposematic mimicry, or mimicry of aggressive resemblances.
Agressive mimicry favors aggression and offers a measure of protection from certain enemies.
Some species produce a loud buzzing sound in flight not unlike some bumblebees. The curious Chilean asilid Lycomya germainii Bigot has for its model the Hymenopteron Elaphroptera scoliaeformis Haliday. The American series of mimics from the southwestern states copy the tarantula huntung wasps of the genus Pepsis Fabricius. These noteworthy insects are large, with black or blue-black bodies and wings strikingly colored a yellowish brown. Besides the robber fly Asilus midas Brauer, the series contains Mydas xanthopterus Loew, two large staphylinid beetles, and a large, conspicuous ichneumonid-type wasp.