MUSEUM OF COMPARATIVE ZOOLOGY. 



307 



the so-called Cenlurus subelcgans of Lower California and Mexico. It is 

 interesting to note that variations in color occur between the northern and 

 southern representatives of Centurus Jlaviventris similar to tl\ose exhibited 

 by northern and southern examples of C. carolinus. The southern forms 

 of C. Jlaviventris were long since characterized by Wagler, Swainson, and 

 Bonaparte as specifically distinct from the northern, under the names of C. 

 elegans, C. santacruzi, etc., etc., which many authors still rank as species. 



76.* Melanerpes erythrocephalus, Swainson. Red-headed Wood- 

 pecker. 

 Rare in winter ; said to be common in summer. I saw two only, 

 about March loth. Mr. Boardman also gives it as rare, while Mr. 

 Maynard did not meet with it at all. Audubon speaks of its being 

 very abundant in winter in Louisiana, and Dr. Coues gives it as resi- 

 dent in South Carolina ; but it is certainly not common in winter in East 

 Florida. 



77.* Colaptes auratus Swainson. Golden-winged Woodpecker. 

 Abundant. 



Considerably smaller than at the north, with the colors much more in- 

 tense, and the transverse black bars on the back relatively broader. The 

 individual variations in this species, even at the same locality, are very 

 considerable, especially in respect to the bill. Figures 5 and 6, Plate VIII, 

 illustrate the variation in the form and size of the bill of two specimens 

 from Massachusetts, both of which are females. 



The following summary of the subjoined tables indicates the difference 

 in size between Massachusetts and Florida specimens, and the individual 

 differentiation in the same respect at each locality. The sexes seem not 

 to differ essentially in size. 



"While the Florida specimens are considerably smaller than the northern 

 in three of the measurements, the tail is actually longer in the Florida 

 birds, and hence relatively much longer. In most of the species of which 

 comparative tables of measurements are given in the present paper, there 

 is a decided tendency to an elongation of the tail at the southward, the 

 tail decreasing less in length than the wing or the general size. 



