Hornet hornets may often be black and white. There is also a related genus of Asian nocturnal vespines, "Provespa", which are referred to as "night wasps" or "night hornets", though they are not true hornets. Some other large wasps are sometimes referred to as hornets, most notably the bald-faced hornet ("Dolichovespula maculata") found in North America. It is set apart by its black and ivory coloration. The name "hornet" is used for this and related species primarily because of their habit of making aerial nests (similar to the true hornets) rather than subterranean nests. Another example is the Australian hornet ("Abispa
Bald-faced hornet acts as a selective pressure on the workers, so they are more likely to exercise reproductive restraint. It has been suggested that workers in reproductive nests may kill their queen so they can reproduce. When researchers at the University of Sheffield examined a collection of nineteen "D. maculata" nests during the reproductive phase of their life cycle, they found that 14/19 nests did not have a queen. Matricide might occur after sufficient workers have been raised and queen-destined eggs have been laid. However, matricide has not been directly observed and other causes of death are possible. Diet in "D. maculata"