1886.] CUBITAL COVERTS OF BIRDS. 187 
species of Passerine birds, and will probably, on further examination, 
be found to characterize the whole of the birds that are correctly 
referred to that Order. 
In the Corvidze an approach towards a somewhat different mode of 
arrangement is made (fig. 3): another minor modification is seen in 
the Alaudidee (fig. 3a). The Swallows (fig. 5a, p. 188) all appear to 
follow the normal passerine type. That of the Swifts and the Cotingas 
appears to me to be essentially different. There is some doubt also 
in regard to the Bower-birds and the Birds of Paradise in this 
respect. 
Following Dr. Sclater’s arrangement, the Swifts and the Humming- 
Turdus merula. Corvus. Alauda arvensis. 
birds fall next to be deseribed. Living Humming-birds can very 
rarely be examined closely ; I have therefore been compelled to rely 
entirely upon the examination of museum specimens. After exa- 
mining the whole of the Gould Collection, and checking the results by 
comparing them with those made ona large series of other specimens, 
I am convinced that one general type of wing-pattern characterizes 
the whole of these birds; it is of a very simple character, and is 
represented in figure 4, p.188. By this it will be seen that the proxi- 
mal lapping row of median coverts found throughout all the Passeres 
is absent entirely in this. The Humming-birds might, indeed, be 
described as possessing no median coverts at all, the place of these 
being taken up by feathers having the same mode of imbrication as 
the Lesser Coverts. All the feathers of each series overlap outwards 
and backwards from the vertebral axis towards the distal end of the 
wing in these birds. 
Observations on the order of overlap in the wing of freshly-killed 
specimens of Cypselus apus, afterwards extended by an examination 
of the whole series of Swifts in the National Collection, showed that 
in these, as in the Humming-birds, no one series of feathers overlaps 
backwards. in fact the wing-pattern in the genera Cypselus, 
Acanthylis, Chetura, and Collocalia seems to me to differ in no 
essential respect from that found throughout the Trochilide. So 
far as the disposition of the wing-coverts is concerned, the Swifts and 
Humming-birds agree amongst themselves, and differ from all of the 
Passeriform birds, with the possible exception of the Birds of Paradise. 
Fig. 5, p. 188, taken from a freshiy-killed specimen of Cypselus apus, 
will serve to make this point clear. A wing of Hirundo rustica is 
figured alongside for comparison (fig. 5 a). 
Ia 
