370 Mr. O. Salviu on the Birds of the 



has a decided tendency to acquire a barred rump (M. leei, 

 Ridgw.) ; but in the series before me 1 find every gradation 

 to the typical form. As the extreme varieties of this Wood- 

 pecker occur together on one small island, a trinomial for it 

 seems out of place. A distinct binomial, again, for one ex- 

 treme form is not sufficient, without admitting the other 

 extreme as coexisting in the same area, and then we have 

 the further difficulty of dealing with the intermediate forms 

 which are neither the one nor the other. The only way out 

 of the difficulty is to call them all by the comprehensive 

 name C. diibius. 



The range of C. dubius is very extensive. Recent Mexican 

 collections contain specimens from Teapa and from as far 

 Avest as Playa Vicente, in the State of Vera Cruz. Here it 

 almost touches the range of C. santacruzi, which is found 

 near the town of Vera Cruz, at Atoyac, on the railway to the 

 interior, and thence northwards along the coast to Tampico. 

 In the Eastern Sierra Madre, near Victoria, C. aurifrons 

 occurs, the prevalent species of the Rio Grande valley and 

 the interior of Northerm Mexico. 



-f-127. Centurus canescens, sp. n. 



r C. dubio affinis, sed fasciis albis corporis superioris et alarum 



latioribus, remige tertio ad basin distincte albo fasciato, 



genis et corpore toto subtus plerumque albicautioribus, 



ut videtur, distinguendus. 



Hab. Ruatan I., Bay of Honduras (G. F. Gaumer). 



Mr. Gaumer's collection from Ruatan Island contains a 



large number of specimens of this Woodpecker, which, 



though closely allied to C. dubius, seems separable as an 



island-form, the characters, taken together, being sufficient 



to distinguish it. The pale colour of the cheeks and under 



plumage, compared with that of C. dubius, at once strikes 



the eye as a distinctive character, but we have a specimen or 



two from the mainland nearly, if not quite, as pale. The bar 



at the base of the third primary is more certain, this feather 



being nearly black in C. dubius. 



This Woodpecker being restricted to the island of Ruatan, 

 the slight characters by which it can be distinguished arc of 



