30 ON SOME HABITS OF A PELOPffiUS, 



to its own length, and all parts of the edge are equally distant 

 from the base, it bends in the outer edge until the aperture barely 

 admits of the passage of its own body. 



Beneath this cell are built two, or sometimes three others in a 

 roughly horizontal row ; then another row containing more cells 

 than the one above it, and so on until the nest has reached the 

 required maximum breadth ; when the number of cells in each 

 row diminish, until on the completion of the whole it is in shape 

 a rough oval. The mandibles appear to be the principal building 

 organs, as they are used to press the mud to any required 

 thickness. The anterior tarsi before mentioned and the antennas 

 are also largely used ; the tarsi support the load of building 

 material, which is about the size and shape of a small pea, during 

 transport; they also assist the mandibles in shaping. The 

 antennae are, no doubt, the final smoothing and polishing 

 instruments ; they beat the mud with such velocity as to render 

 their motion almost invisible, and create a loud humming noise. 



I may remark here, that in the construction of cells, the 

 antennae do not appear to be the organs of sensation, which 

 determine when the wall of the cell has arrived at the required 

 thickness. The anterior tarsi, judging from their movements, 

 perform this office ; from which it would appear that in Pelopoeus 

 Icetus these tarsi are capable of conveying sensation, of a kind 

 usually, I believe, accredited, in all insects, to the antennae alone. 



On one occasion, while the hornets were in search of more 

 material, I pressed a portion of the edge of a cell, in course of 

 construction, out of shape. On the return of the first one the 

 damage was detected, apparently by sight, almost instantly ■ he 

 seemed for a time quite nonplussed, but presently he deposited 

 and arranged his load in another place and then repaired damages. 



Again I repeated this experiment, but on his return this time 

 he showed no hesitation whatever ; took in the situation at a 

 glance, as it were ; deposited and arranged his load on the intact 

 portion of the edge of the cell, then repaired the damage. He 

 alighted and went to work with such rapidity that I thought the 



