PICID^: WOODPECKEBS. 
485 
unbarred, the outer white, the central black. All the species of this genus are unquestionably 
modified derivatives of one circumpolar stock ; the American seem to have become completely 
differentiated from the Asiatic and European, and further divergence seems to have perfectly 
separated arcticus from americanus ; but dorsalis and americanus are still linked together. 
Analysis of Species. 
Back uniform black arcticus 443 
Back with entirely interrupted lengthwise white stripe americanus 444 
Back with nearly or quite uninterrupted lengthwise white stripe dorsalis 445 
443. P. arc'ticus. (Lat. arcticus, arctic.) Black-backed Three-toed Woodpecker. Entire 
upper parts glossy blue-black, with only a few white spots paired on the wing-quills. Below, 
white from bill to tail, the sides, flanks, and lining of wings barred with black. A slight or 
concealed white post-ocular stripe ((jften wanting) and a side-stripe on head from across fore- 
head to neck, cut off by black from the white of the under parts. Four middle tail-feathers 
black, the rest white, but the intermediate one usually touched with black. ^ with a square 
yellow patch on crown, wanting in 9 • Bill and feet blackish-plumbeous ; iris brown. Length 
9.00-10.00; extent 15.00-17.00"; wing 5.00-5.50; tail 4.00; bill 1.25 or more. Northwestern 
Am., S. in winter through New England and generally along the northern tier of U. S., in the 
mountains of the West to about 39° in Nevada and California. Habits of ordinary Picus. 
Eggs 0.92 X 0.72. 
444. P. america'nus. (Of America.) Ladder-backed Three-toed Woodpecker. Upper 
parts black, the middle line white, more or less completely barred across with black ; the 
general effect thus of a ladder-back." All the primaries and secondaries with paired white 
spots or bars. Four middle tail-feathers black, others white, the intermediate one usually 
touched with black. Below, white from bill to tail, the sides, flanks, and lining of wings 
black-barred. A white post-ocular stripe to nape, and a larger white stripe from lore to side 
of neck. ^ with a yellow square on crown, wanting in 9 j hoth, crown seldom uniform 
black. Bill and feet blackish-plumbeous; iris brown. Smaller than the last ; length 8.00- 
9.00; extent 14.00-16.00 ; wing 4.50-5.00 ; tail under 4.00; bill 1.25 or less; whole foot 1.50. 
Northern N. Am., S. to Massachusetts and along northern tier of States. 
445. P. a. dorsa'lis. (Lat. dorsalis, relating to dorsum, the back.) Pole-backed Three- 
toed Woodpecker. In extreme case, the back with an uninterrupted white lengthwise 
stripe, producing the effect of a ^' pole-back," as in P. villosus for instance; this is produced by 
such increase of white on the ends of the individual feathers that their black bases do not show, 
the subterminal black bars of P. hirsutus disappearing. Usually partly banded black and 
white, and grading bar by bar into hirsutus. The amount of spotting on the wings is about 
, as in Picus harrisi — on primaries and secondaries, not on coverts. Size of hirsutus. Kocky 
Mt. region, U. S., S. to New Mexico. 
154. SPHYROPI/CUS. (Gr. acjiipa, sphura, a hammer; and Lat. picus.) Sap- SUCKING Wood- 
peckers. Bill about as long as head, not so stout and chisel-like as in the foregoing genera ; 
pointed, with little bevelling at extreme end only, and lateral ridges running obliquely into the 
commissure at about its middle ; culmen and gonys both a little curved ; nasal tufts moderate. 
Wing pointed by 4th primary; 3d and 5th nearly as long; 2d between 6th and 7th; spurious 
1st very short. Tail-fejithers long-acuminate. Outer hind toe little longer than outer front 
one ; inner hind toe extremely short. Plumage highly variegated with yellow and red. Sexes 
unlike. Tongue scarcely extensile ; the tip obtuse, brushy ; hyoid bones short. Birds of this 
remarkable genus feed much Upon fruits, as well as insects, and also upon soft inner bark 
(cambium) ; they injure fruit-trees by stripping off the bark, sometimes in large areas, instead 
of simply boring holes. Of the several small species commonly called sapsuckers," they alone 
deserve the name. In declaring war against woodpeckers, the agriculturist will do well to 
discriminate betM^een this somewhat injurious and the highly beneficial species. 
