Mr. Jenyns on the Ornithology of Cambridgeshire. 307 
Spe.81. H. urbica, Temm. Man. @Ornith. p. 428. 
Hovusrt Martin.—This appears about a weck after the swallow, 
but is seldom in great plenty before the beginning of May. It 
however remains with us later than that species, and is occasionally 
seen through the first week in November *, though the greater 
part withdraw before that time. Previously to migration they 
congregate upon the roofs of houses and churches. 
Sp.82. H. riparia, Temm. Man. @Ornith. p. 429. 
Sanp Martin.—The only places where I have hitherto observed 
these birds in Cambridgeshire, are the chalky banks by the side 
of the road near Quy Water, and some gravel-pits in the neighbour- 
hood of Bourn Bridge. In the former of these situations I have 
noticed them regularly every year, and have found the time of 
their arrival to be about the middle of April, but I am unable to 
say when they leave us, though I am inclined to suspect that this 
takes place at a much earlier period than with either of the pre- 
ceding species. 
Genus XXVIII. CYPSELUS, Illig. 
Sp.83. ©. murarius, Temm. Man. d@’Ornith. p. 434. 
Swirt.—This species is by far the latest in its arrival of all the 
Swallow tribe, as I never remember to have seen it before the 
seventh of May. Generally speaking it is equally remarkable for 
its early departure, withdrawing from most places by the begin- 
ning of August, and often by the end of July. A singular excep- 
tion, however, to this last mentioned circumstance takes place 
with respect to these birds in the neighbourhood of Ely, where 
the bulk of them hardly ever retire till quite the end of August, 
and a few individuals may often be observed through the first 
week in September}. From what cause they are induced to pro- 
* Dr. Thackeray informs me that he has known three or four individuals stay about 
the south side of Clare Hall till the eighteenth of this month. 
+ A single bird has also been noticed by Dr. Thackeray about King’s College Chapel 
for many successive days during the early part of September. 
Vol. If. Part I. Rr 
