XIX.] 
LETTER XIX. 
TO THOMAS PENNANT, ESQ. 
I HAVE now, past dispute, made out three distinct species of 
the willow-wrens (Motacilkv trocliili) which constantly and in- 
variably use distinct notes ; but, at the same time, I am obliged 
to confess that I know nothing of your willow-larlv.^ In my 
letter of April the ISth, I had told you peremptorily that I 
THK WILLOW-WREX. 
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 other two, and 
the yellow-green of the whole upper part of the body is more 
^ Brit. Zool., edit. 1776, octavo, p. 381. 
Hedge-warbler, (see Letter XXVI.) : Sylvia loguax, black legs ; Sijlvia 
trochilus, yellowisli belly ; Sylvia sibilafrix, white belly. 
