Orthotonus Horsfield, Trans. L. S., xiii, p. 165 (1820;. Type, O. sepium Lafres.
The genus Orthotomus has been divided into two genera, Orthotonus and Sutoria, the former containing those species which never attain a long tail in Summer, and the latter those which do. The acquisition of long tail-feathers is, however, a feature of little importance and is bridged over by maculicollis which seldom* acquires a long tail and then only to a degree of length much less than in sutorius. North-Western birds have the longest tails and Eastern birds the shortest. In this genus the bill is as long as the head, broad and rather flat; there are a few rictal bristles but no supplementary hairs and the forehead is very smooth and flat. There are long soft hairs springing from the nape; the wing is very short and rounded, the first primary large and the fourth and fifth longest and subequal; the tail of twelve feathers is much graduated; the tarsi are strong and long.
Key to Species.
A. Upper plumage suffused with green.
a. Under wing-coverts, axillaries and under
tail-coverts yellowish white ………………..O. sutorius, p. 410.
b. Under wing-coverts, axillaries and under
tail-coverts bright yellow O. atrigularis, p. 414.
B. Upper plumage ashy-grey.
c. Tail chestnut ………………………..O. ruficeps, p. 415.
d. Tail brown O. sepium, p. 416.