none Fourteen of 18 colonies of V. consobrina (Saussure) had nests that were subterranean, all constructed in rodent burrows, while 4 were aerial. The average number of cells for 15 mature nests was 703, range 308-1368. This is considerably smaller than nest sizes reported for other members of the V. rufa species group in North America. Number of workers in mature colonies ranged from 53-97. The upper limit for workers is probably 200 or less. V. consobrina , in regard to nesting biology and behavior, is a typical V. rufa species group member. The only unique behaviors observed were a general level of hyperactivity as compared to other studied yellowjacket species, and the ability of workers from some colonies to hover in flight, a behavior perhaps adapted to their usual foraging habits. In addition, unlike typical yellowjacket queens, the queen of one small colony physically dominated (mauled) her workers. Reproduction; Reproductive behaviour; Breeding site; Behaviour; Social behaviour; Associations; Ecology; Habitat utilization; Land and freshwater zones; Nearctic region; North America Fannia canicularis (Fanniidae ); Triphleba lugubris (Phoridae ); Nest and burrow fauna; Vespula (Hymenoptera) nest; USA Sphecophaga vesparum burra (Ichneumonidae); Nest and burrow fauna; Vespula nest; USA Vespula (Vespidae); Nest and burrow fauna; Triphleba lugubris & Fannia canicularis (Diptera); Sphecophaga vesparum burra; Habitat preference; USA, social behaviour & nest parasites Vespula consobrina (Vespidae); Nesting site; Subterranean & aerial colonies; Social organization; Colonies, composition & behaviour; USA