112 HYMENOPTERA CHAP. 



the interiors of human habitations as the spots most suitable for 

 the formation of their own domestic establishments. Fabre has 

 given a charming account of the habits of Pelopaeus (Sceliphrori) 

 spirifex, a species that inhabits the South of Europe, and that forms 

 its nests in the cottages of the peasants. The spot usually selected 

 is a nook in the broad, open fireplace, out of reach of the names, 

 though not of the smoke ; here the Pelopaeus forms a nest of 

 earth, consisting of ten to fifty cells, the material being mud or 

 clay brought in little balls by the aid of the Insect's mandibles ; 

 about twenty visits are required in order to complete one cell, so 

 that for the construction of a large nest of fifty cells, about one 

 thousand visits must be made by the Insect. It fiies in and 

 out of the house apparently not at all incommoded by the 

 human habitants, or by the fact that the peasant's potage may 

 be simmering on the fire quite close to where the fearless little 

 creature is carrying on its architectural operations. The cells 

 are stored with spiders, of which the wasp has to bring a plentiful 

 supply, so that its operations extend over a considerable period. 

 The prey is captured by the Pelopaeus whilst on the wing, and 

 carried off at once, being probably stung by the wasp during 

 the process of transit ; apparently it is killed by the operation, 

 not merely paralysed. Only small spiders are taken by this 

 species, and the larva of the Pelopaeus consumes them in a short- 

 time, one by one, before the process of decomposition sets in ; 

 the egg, too, is laid on the first spider introduced, and this is of 

 course at the bottom of the cell, so that the spiders are eaten by 

 the wasp's larva in the order in which they were brought to the 

 cell. The cell is sealed up when full, the number of spiders 

 placed in it being on the average about eight. The larva 

 completes its task of consuming the store in about ten days, and 

 then forms a cocoon for its metamorphosis. Two or three 

 generations are produced in a single year, the autumnal one 

 passing eight or nine months in the clay cells, which are lodged 

 in a nook of the peasant's hearth, and exposed to the smoke of 

 his fire during all the months of winter. Pelopaeus (Scelipliroii] 

 is a genus including many species ; * several of them are known 



1 Pelopaeus disappears from the new catalogue of Hymenoptera as the name of a 

 valid genus ; its species being assigned to Sceliphron and various other genera. 

 Wo have endeavoured, as regards this name, to reconcile the nomenclature of 

 previous authors with that used in the new catalogue by placing the generic name 

 adopted in the latter in brackets. 



