94 



N Ai UR AL li ISTOU Y 



LETTER XIX. 



TO THE SAME. 



'DEAR SIR; Selborne, Aug. 17, 1768, 



I HAVE now, past dispute, made out three 

 distinct species of the willow-wrens C mota- 

 cilia; trochili J which constantly and invari- 

 ably use distinct notes. But, at the same 

 time, 1 am obliged to confess that I know 

 nothing of your willow-lark.* In my letter 

 of April the 18th, I had told you peremp- 

 torily that I knew your willow-lark, but 

 had not seen it then : but, when I came 

 to procure it, it proved, in all respects, a 

 very motacilla trochilus ; only that it is a 

 size larger than the two other, and the yel- 

 low-green of the whole upper part of the 

 body is more vivid, and the belly of a 

 clearer white. I have specimens of the 

 three sorts now lying before me ; and can 

 discern that there are three gradations of 



* Brit. Zool. edit. 1776, octavo, p. 381. 



