Geographical Distribution in Birds, 41 
this increase in the extent of red, there is also a gradually 
increased amount of black, strictly parallel to that in Picus 
villosus (var. Harris) and P. pubescens (var. Gairdner?) from the 
same regions (see vol. iv, p. 456). 
the rump, primaries, abdomen and tail-coverts. is form 
becomes more specialized, by the exaggeration of these char- 
acters, as it reaches its southern limit. In the conspicuously 
streaked forehead, lengthened crest, ashy body, and contras 
shades of blue, this form approximates closely to 
4 white supraocular spot, barred greater coverts, or other pecu- 
liar features of the Rocky Mountain and Mexican form. That 
