80 LETTERS ON ENTOMOLOGY* 
and as they increase in number, are taken down 
and rebuilt. They differ from all the rest in 
being made of particles of Wood, apparently 
joined together with gums. Intermixed with 
these are the magazines formed of clay, and con- 
taining particles of wood, gums, and the in- 
spissated juices of plants. These apartments, 
separated by small empty chambers and galleries, 
are continued on all sides to the outer wall of 
the building, to about two-thirds of its height ; 
leaving, however, an open area in the middle, 
like the nave of a cathedral, supported by three 
or four large Gothic arches, which in the middle 
are sometimes two and three feet high, but on 
each side are diminished like aisles of arches in 
perspective. The floor is so contrived as to let 
any water that may happen to get in run off 
into the subterranean passages, which are of an 
astonishing size ; some being a foot in diameter, 
and quite round and smooth : they were the 
quarries from which they procured materials for 
building, and serve afterwards as the outlets of 
their fortress. As they find great difficulty in 
ascending a perpendicular, they make in the in- 
terior upright part of the building a flat path- 
way, which winds gradually up, like a road 
cut in the side of a mountain. Who will say 
