80 Vnwersiiy of California Publications in Zoology [Vol. 30 



As between the two aggregations, ohscurus and fuligimosus, besides 

 color differences and besides the shape of the tail, so markedly con- 

 trasted in the closely adjacent northern subspecies, account must be 

 taken of the call-notes of the male birds, which are so radically different 

 as to indicate a wide divergence and one of long standing, a specific 

 difference. The reverberant, wooden call of an old "hooter" {D&n- 

 dragapus fuliginos-us) is the same from Alaska to southern California, 

 a sound that carries a half-mile or more, and a very different call 

 from the subdued tooting of the Richardson grouse and its allies. 

 Complementary to this, the relative development of a part of the hoot- 

 ing apparatus, the naked skin on the sides of the neck, is another dif- 

 ference between the two forms (see Brooks, 1912, p. 252 ; 1926, p. 283) . 



It looks as though in all the earlier studies of these grouse the 

 presence of a terminal gray band on the tail alike of obscurios and of 

 fuliginasuis was allowed to outweigh all other features of resemblance 

 or dissimilarity between the several forms. Aside from this, an adult 

 male of oisau.vws is very closely similar to an adult male ricihardsonii. 

 The tail of an adult male obscurus at hand, from Colorado, is nearly 

 as square as in richardsowii, not rounded as in fvMgvnosus. The 

 rectrices of dbscums, however, are not markedly truncate. 



In years past richardsonii has sometimes been regarded as a species, 

 distinct from the several other forms of "blue grouse," all regarded 

 as subspecies of D. ob scurvy, but study of a map outlining the distri- 

 bution of the races will show how illogical such division would be 

 (see fig. A). 



It is curious to what an extent certain of the characters of 

 richardsonii parallel the distimguishing features of Canachites frcmk- 

 limi. This grouse (which is currently regarded as a species, distinct 

 from other forms of Canachites) has developed the same square-tipped 

 tail with broad, truncate feathers, and, besides this striking resem- 

 blance, the distribution of the Franklin grouse is almost the same 

 as in the Richardson grouse; almost, but not exactly, for northward 

 the range of Carmchites franklinii extends well within the territory 

 of Bendragapus o. flenningi. In the northern portion of its range, 

 D. o. flemingi is accompanied by Canachites canadensis osgoodi. 



In differentiating the several subspecies of "blue grouse" (both 

 species) , shape and markings of the tail are useful characters, but to 

 ascribe proper weight to thes^ variations an understanding is necessary 

 of the development of the individual bird, of the stages gone through 

 to reach maturity, as previously indicated in this paper. In both sexes 



