in SPHEGIDAE SPHEGIDES PELOPAEUS 113 



to be specially .attached to the habitations of human beings. 

 Both has given an account of the habits of P. (Scelipliron} 

 laetus in Australia ; he says that in some parts it is very 

 difficult to keep these wasps out of the houses ; the nest is 

 formed of mud, and constructed on the furniture or in any part 

 of a room that suits the fancy of the Insect. This it must be 

 admitted is, according to human ideas, liable to the charge of 

 being very capricious. Both timed a wasp building its nest, 

 and found that it brought a fresh load of mud every two or 

 three minutes. If the wasp be allowed to complete the nest 

 undisturbed, she does so by adding to the exterior diagonal 

 streaks of mud, so giving to the nest the look of a small piece 

 of the bark of a common acacia. The construction consists of 

 from ten to twenty cells, and when completed is provisioned 

 with spiders for the use of the young. This wasp is much 

 pestered by parasites, some of which prevent the development of 

 the larvae by consuming the spiders intended by the mother- 

 wasp for its young. A fly, of the Order Diptera, is said to follow 

 the wasp when carrying a spider, and to deposit also an egg on 

 the food : as the Dipterous larvae have more rapid powers of 

 assimilation, the Pelopaeus larvae are starved to death ; and their 

 mildewed remains may be found in the cell, after their enemies 

 have become fully developed and have flown away. Another 

 parasite is said to eat the wasp-larva, and attains this end by 

 introducing an egg through the mud wall and the cocoon of the 

 wasp a habit that seems to indicate a Leucospid parasite. 

 Tachytes australis, a wasp of the sub-family Larrides also dis- 

 possesses this Pelopaeus in a manner we shall subsequently 

 describe. This fragment of natural history from Australia has 

 a special interest, for we find repeated there similar complex 

 biological relations to those existing in the case of the European 



congeners. 



P. (SceUpliroti) madraspcdanus is common in the north-west 

 provinces of Hindostan, and is called the " mud-dauber " by the 

 European residents. According to Home it constructs its cells in 

 the oddest places, but chiefly about the inhabited apartments in 

 houses. It is perfectly fearless when engaged in building : the 

 cells are four to six in number, and are usually provisioned with 

 spiders to the number of about twenty. On one occasion 

 it was observed that green caterpillars were stored instead of 



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