162 MESSES. C. HOENE AND F. SMITH ON HTMENOPTEEA 



removal of a lock, a hollow between bricks, or between the wall and door-frame. 

 Sometimes a roughness or slight depression in the floor is the unfortunate selection, 

 where the first passer by will crush the construction, in which case the patient creature 

 will rebuild it three or four times, and at last, in despair, abandon the locality ; thus 

 on one occasion I observed a cell built in the corner of the door-frame of a bath-room, 

 so that it must be crushed every time the door was closed. The room was used at least 

 once a day ; and six times was the cell completely destroyed ; it then abandoned the 

 position. This was in October 1867 ; and I rather think that it ceased building merely 

 in consequence of its season for cell-building having expired. 



Sometimes each cell is separately constructed ; at others one is placed over another ; 

 whilst I have observed them, as hereinafter described, build a mass of cells, as in the 

 case of the corner of a room being selected. 



The building of these cells is very regularly conducted, and they are generally placed 

 parallel to the ground. A line of pellets of mud, the base of the ceU, is first put down, 

 and each pellet is worked nicely and smoothly with the jaws, assisted apparently by the 

 feet, so that, as the work is performed very quickly, the joins are hardly perceptible. 

 Having finished off its work with one pellet, it stands over it, looks at it with com- 

 placency, walks around it, pats it approvingly with its antennse, and at last, being 

 satisfied, flies off for more material. 



I have reason to think that generally but one sex works at nest-building; for often, 

 when I have captured an insect at work, no other has come to complete the structure. 



A cell takes about a day to make, the insect working assiduously as long as daylight 

 lasts. As the walls rise, layer by layer, they are contracted until they meet in an arch, 

 the insect meanwhile carefully smoothing and plastering the interior as the work 

 proceeds. 



The next employment is the filling of the cell with food for the young grub. On 

 one occasion only I observed green caterj)illars being stored, although small field-spiders 

 are the regular storing-food. 



The egg would appear to be deposited on the body of the first spider placed in the 

 cell. This would lead one to infer that the female is the worker. 



Twenty spiders are sometimes packed away ; and the egg or young grub of the insect 

 has always been found by me on the lowest one when I have opened a cell directly 

 after it has been closed up, which closing is effected directly the structure is well filled. 



Ordinarily, on one cell being finished another is begun alongside, as little space being 

 lost as possible ; and in this way four, five, or six cells are made. 



Meanwhile the egg is hatched, and the young grub sucks out, one by one, the juices 

 of the comatized spiders, until being fully grown and its stores finished, it spins its 

 strong cocoon of fine agglutinated silk and changes into the pupa-state. In this it 

 remains for periods varying from one to five months according to season. 



When the time for emerging arrives, the cap of the pupa-case gives way to the jaws 



