6646 



Insects. 



might select as specimens of the different tissues. These have appa- 

 rently been all pulled singly from plants, either growing or still 

 retaining their sap ; for the paper made by these wasps strikes a dark 

 colour on being boiled in an alkaline solution to dissolve the mucus 

 by which the fibres are held together. An irregular kind of felting 

 of the component fibres gives the structure additional tenacity. 



The fabric of V. Crabro and V. vulgaris is made of minute frag- 

 ments, not filaments, cut, rather than torn, from dry and rotten wood. 

 With this material V. vulgaris makes a light yellow, brittle paper, 

 which feels harsh and gritty, and crumbles under the hand into 

 powder. V. Crabro fastens together large grains of sand and wood 

 into a structure which is, in general arrangement, a coarse exaggera- 

 tion of the paper of V. vulgaris, and owes its strength almost entirely 

 to the dark gummy secretion in which these fragments are set, like 

 stones in concrete. Where the structure is thick, as in the pillars, it 

 possesses very considerable strength, but hornet paper is very friable. 



The case of the nest of V. britannica is well adapted to the cir- 

 cumstances under which it is usually placed. Being of a dull mottled 

 brown and gray colour, it is unlikely to attract notice ; and being 

 formed of separate sheets overlapping one another, composed of a 

 substance not indeed impervious to water but insoluble in it, the 

 structure is well calculated to protect the enclosed comb from any 

 injurious effects of rain. The underground nest of V. germanica is, 

 in its turn, equally fitted to resist the injurious influences of a wet or 

 crumbly soil, to which it is most likely to be exposed. In the tree- 

 wasp's nest we have unconnected sheets, overlapping one another 

 like the capes of an old-fashioned box-coat. In the ground-wasp's 

 the wall is made of large flattened cells, built one upon another to 

 the thickness of half an inch or more, not affording equal facilities 

 for drying, for indeed probably they never are dry, but capable of 

 sustaining a greater pressure than the case of the tree-nest could 

 bear, and giving more points of support by which the nest may be 

 attached to the irregularities of the cavity in which it is usually built. 

 Instead of a smooth ball, resembling a half-blown rose or a cabbage, 

 the nest of V. germanica forms a rough dirty-looking mass, covered 

 over with shelly patches, laid on without the slightest pretension to 

 order or appearance. When it builds in roofs, a less usual situation, 

 it retains the cellular mode of construction, as instinct guides it; and 

 indeed, in a situation protected from rain, this cellular structure 

 would answer the purpose intended quite as well as a laminated one. 

 I3ut the form of these cells undergoes certain modifications, according 



