THE HOUSE-MARTINS. 
3 2 7 
Kest.— ' This is described by Mr. Seebohm as a “ very hand- 
some little structure, almost entirely formed of green moss, with 
here and there a few scraps of lichen, and a downy feather or 
two. The inside is sparingly lined with fine dry grass and 
hairs. The nest-cavity measured about two inches in dia- 
meter, and one and a-half inch in depth. 
Eggs.— From five to seven in number. They approach in 
colour the eggs of the Robin and the Common Flycatcher, but 
are not so heavily marked as those of the latter bird. 1 he 
ground-colour is greenish-white, with reddish spots and blotches, 
sometimes collecting round the larger end. Others are nearly 
uniform creamy-buff, clouded with obscure reddish mottling. 
Axis, 0-65-07 inch; diam., 0-55-06. 
THE SWALLOWS. FAMILY HIRUNDINID/E. 
These birds differ considerably from the other Passeriformes, 
and they possess a striking difference in their pterylosis, the 
spinal feather tract being forked on the back. The primary- 
quills are only nine in number, the tail-feathers twelve. The 
bill is broad and flat, and the gape is very wide as with 
Swifts and Goatsuckers, which, like the Swallows, catch their 
food on the wing, The front of the tarsus is smooth, and the 
hinder aspect is bilaminated longitudinally. Swallows are 
found in nearly every portion of the globe, from very far noith 
to very far south. In the northern portion of their range they 
are strictly migratory, and only come in summer, and, unlike 
other Passerine birds, they moult only in their winter home, 
and do not renew their plumage in the autumn before taking 
their long journey southward. 
THE HOUSE-MARTINS. GENUS CHELIDON. 
Chelidon , Boie, Isis, 1822, p. 550. 
Type, C. urbica (Linn.). 
The House-Martins are very easily recognisable by their 
feathered feet and toes, and by the broad white band across 
the rump, which is very conspicuous when the birds are flying. 
There are five species of Chelidon , one, C. urbica, being the 
sDecies which visits England ; a second, C.dasypus, represent- 
ing it in Tapan and the far east; while the intermediate area 
is occupied by the Siberian House-Martin, C. lagopus. Two 
