11. Pyrrhula cassini. ♂ Alaska (Nulato), 49955.
12. Pyrgita domestica. Europe.
In the intensity, as well as the shade of the red in the males, there is a great range of variation. Generally it is of a tint almost precisely like that of L. curvirostra, though deeper. The most highly colored specimen is 54,795, Philadelphia (J. H. McIlvaine), which is entirely continuous deep tile-red, approaching vermilion on the rump. The abdomen and crissum are light pinkish. In No. 31,459, Fort Rae, April, the red is of a curious and very unusual purplish wine-red shade.
The average of western specimens, particularly those from the northwest coast of the United States, have bills scarcely larger than in the average of eastern examples; thus, 18,037, Fort Crook, N. Cal., has the bill of the same size as No. 5,803, Philadelphia, while No. 53,482, East Humboldt Mountains, has the bill smaller than any other in the collection.
In color, there are scarcely any tangible differences between the European Loxia curvirostra and the two American varieties, the distinctive character being in the form of the bill and the size; the C. mexicana is the largest of the three, and the bill is quite peculiar in form, the lower mandible almost equalling the upper in length, and exceeding it in thickness. L. curvirostra is slightly smaller, and has the lower mandible much smaller and less, powerful than the upper, being inferior to it both in length, breadth, and thickness. The colors also appear to be rather less intense than in C. mexicana.
The C. americana is in every way, the bill especially, smaller than either of the preceding. The lower mandible, although but slightly shorter than the upper, is still much weaker, as in the European bird. The majority of western birds have the bill but slightly larger than eastern, and most of those with large bills are only intermediate between americana and mexicana. In some specimens the bill, although almost equalling in length that of the latter, has yet the form of the former; on the other hand, there are specimens with the proportions of the mandibles as in mexicana, while the size is intermediate.