52 



INSECT ARCHITECTURE. 



found that the nests were furnished, like those of the 

 same tribe, with balls of pollen kneaded with honey, 

 as a provision for the grubs. 



The female ceratina selects a branch of the bramble 

 or wild-rose which has been accidentally broken, and 

 digs into the pith only, leaving the wood and bark 

 untouched. Her mandibles, indeed, are not adapted 

 for gnawing wood; and, accordingly, he found in- 

 stances in which she could not finish a nest in 

 branches of the wUd-rose, where the pith was not of 

 sufficient diameter. 



The insect usually makes her perforation a foot in 

 depth, and divides this into eight, nine, or even 

 twelve cells, each about five lines long, and sepa- 

 rated by partitions formed of the gnawings of the 

 pith, cemented by honey, or some similar glutinous 

 fluid, much in the same manner with the xylocopa 

 violacea, which we have already described. 



Carpenter- Wasps. 



As there are mason-wasps similar in economy to 

 mason-bees, so are there solitary carpenter-wasps 

 which dig galleries in timber, and partition them out 

 into several cells by means of the gnawings of the 

 wood which they have detached. This sort of 

 wasp is of the genus Eumenes. The wood se- 

 lected is generally such as is soft, or in a state of 

 decay; and the hole which is dug in it is much less 

 neat and regular than that of the carpenter-bees, 

 while the division of the cbambers is nothing more 

 than the rubbish produced during the excavation. 



The provision which is made tor the grub consists 

 of flies or gnats piled into the chamber, but without 

 the nice order remarkable in the spiral columns of 

 green caterpillars provided by the mason-wasp 

 (Odinerus murarius). The most remarkable cir- 

 cumstance is, that in some of the species, when the 



