Don't press this alarm... Never squash a Yellowjacket wasp near the nest. A dying yellowjacket releases an alarm pheromone, or smell, that alerts other wasps. In less than 15 seconds, yellowjackets within a 15-foot radius will come to the victim's aid. The yellow jackets and hornets belong to the family Vespidae. The yellow jackets are in the subfamily Vespinae. They consist of four genera: "Provespa, Vespa, Vespula and Dolichovespula."