190 
ON THE CLASSIFICATION OF BIRDS. 
There is something very ingenious in the construction of 
this opening, which is not, as it first appears, round, hut 
semicircular (^fig. 89 - )3 the arch being bound round with 
a stronger hand than usual, and the plane, or base, much 
stronger, and composed of straight pieces of the stalks of 
grass, evidently for the purpose of giving to that part 
upon which the birds perched greater strength and sub- 
stance. Mr. Harrow, as we have seen, remarks that 
lateral openings to the nests of the African birds are 
very common. The rains of Southern Africa and of 
tropical America are, perhaps, equally violent while they 
continue; but then the small leaved and scanty foliage of 
the trees in the former, leave the nests of such birds 
that are upon them much more exposed to these torrents 
than are the nests of the Brazilian birds, where the foli- 
age of the trees is particularly thick and broad. May 
not this be one of the causes, at least, t.-hy nature has 
so especially taught the African birds to construct their 
nests in the manner alluded to Snakes are equally 
common in both regions, yet with the exception of the 
hangnests and a very few others, as Synaltaxis garrnlus, 
Donacnhim voci/eranx, &c., we are unacquainted with 
any other Brazilian birds which depart from the ordi- 
nary style of building. 
(1 63.) Hive nests are constructed alone by such birds 
as live in vast societies under one common roof. They 
are only to lie met with in Africa ; and although Patter- 
son, who first discovered them, gives us a very intelli- 
gible account of their construction, yet what he has said 
of the bird or birds by whom they are built, is too 
vague to enable a modern ornithologist to understand 
either their genera or their species. Hence the name of 
Republican f¥rosheak has been applied to several totally 
distinct sorts. Patterson s account of these extraordinary 
nestsisasfoUows:—'^ The industry of these birds seems 
almost equal to that of the bee. Throughout the day 
they appear busily employed in carrying a fine species 
of grass, which is the principal material they employ for 
the purpose of erecting this extraordinary work, as well 
