334 Letters, Announcements, S^c. 



Boston, June 13th, 1872. 

 Dear Sir, — Your interesting monograph of the genus Geo- 

 thhjpis came in opportune explanation of some remarkable phe- 

 nomena in the flight of the Dendrceca castanea along the 42nd 

 parallel during the present spring, and in confirmation of the 

 hypothesis by which we accounted for them. So far as I know, 

 up to the present year this bird has been very rare in Massa- 

 chusetts. Such an indefatigable collector as Mr. Maynard in 

 the course of his life has obtained but one bird. It is not, 

 however, a rare bird in the northern parts of Maine, nor about 

 Lake Superior, abounding there in the breeding-season. Why 

 is this bird so common three or four degrees north of us, yet 

 so rare here ? From Northern Illinois and Southern Wisconsin 

 came the same story. The D. castanea, unknown there in spring, 

 was this year very common — here between May 25th and 28tJ], 

 there a little earlier. The explanation was, that this Warbler, 

 which passed north the last of the migrants, made a long flight, 

 without stopping or pausing, and went through here in the night 

 — that this year something deranged its flight, so as to make our 

 latitude the area of its halt before its last northern movement. 

 Flocks were seen containing nearly fifty individuals. One of 

 my young friends shot twelve in a single morning. They were 

 all, too, in full song, though unmated, the males bringing up 

 the rear. It was interesting to see bow your statements, as re- 

 gards some species passing by Mexico and Guatemala in their 

 return to the south, seems to confirm our explanation. In 

 Wisconsin D. castanea is not rare in the fall, with us it is so. 



Yours very truly, 



T. M. Brewer. 



Sir, — A small flock of Pallas's Sand-Grouse {Syrrhaptes para- 

 doxus) was observed for about a fortnight on the coast of North 

 Northumberland, opposite the Fern Islands, from the last week 

 in May till about the 6th of June. The birds confined them- 

 selves to the low flats on the mainland, never being observed 

 on the islands. They were much persecuted, and consequently 

 very wild. About the end of the first week of June they dis- 

 appeared altogether. Only one of the flock was obtained. This 



