THE SOCIAL INSECTS 



colonies and the more usual Polybia type was in their small 

 size rather than in the number of queens or in the absence of 

 swarming. The normal nest of a Polybia wasp in British 

 Guiana consists of 300-3,000 cells with 50-1,000 wasps. 

 One of the moderate-sized nests of Polybia rejecta consisted 

 of 7,758 cells and contained about 1,400 wasps. The most 

 populous nest we studied, belonging to another species, 

 had about 21,600 cells and 7,087 wasps of which 93 were egg- 

 laying queens. It seems to be a rule that Polybia colonies 

 are larger in the sub-tropical regions than they are in the 

 rain-forest near the equator. Some, for instance near Rio 

 de Janeiro, may be very large, with probably tens of thou- 

 sands of wasps. Some of the nests are over a yard long and 

 hang from trees like gigantic vegetable marrows. 



Most species of Polybia seem to feed on other insects. 

 Sometimes one finds a nest which is temporarily packed 

 tight with winged ants or winged termites. These are caught 

 on their nuptial flight and are probably stored ; such flights 

 are not very frequent and the opportunity is taken to catch 

 a large number. Another group are active hunters for insects 

 and are found foraging widely all over the forest. These are 

 bad stingers and defend their nests with great ferocity. They 

 also bring home pieces of fresh meat or of carrion if they can 

 find it. Yet other species are flower-visitors and collect nectar 

 or fruit juices ; probably most Polybias do this to some 

 extent. A few have become regular collectors of nectar, like 

 the honey bee. The best known species with this habit has 

 been more or less domesticated in Mexico. The colonies 

 often hang in a citrus bush ; they are allowed to grow to a 

 certain size, and are then cut off or smoked out, and the honey 

 is drained off. If a stump of the old nest is left in the bush 

 the wasps will rebuild in the same spot. Apparently the same 

 kind of wasp in more tropical climates stores very much less 



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