Letters, Announcements, ^c. 127 



virffinianus" in the margin of my copy. The only error is in 

 the size; but as the travellers do not appear to have shot an 

 example, they might easily imagine the bird when flying in the 

 air, with its great expanse of wing, to be larger than it really is : 

 I may add that, though the evening, towards twilight, is the 

 chief time of the Night- Hawk's activity, there is scarcely an 

 hour in the day in which I have not occasionally seen it hawking 

 for insects. 



I am. Sir, 



Your obedient servant, 



J. Hepburn. 



Haarlem, Nov. 27tli, 18G8. 



Sir, — The interest taken in hybrids of any species of the 

 Duck-tribe encourages me to inform you of the result of my ob- 

 servations on three between the Mute Swan [Cygnus olor) and 

 the domestic Goose {Anserferus, var. domesticus), which came to 

 maturity*. They were a male and two females. The first 

 fecundated his mother and also one of his sisters. The other 

 female hybrid never laid any egg. The old Goose's eggs were 

 exactly like every other Goose's eggs, and the young birds were 

 true Geese. The hybrid laid, at intervals of three or four days, 

 a great number of eggs, which resembled very much in length 

 and colour those of the Swan. They were rather thinner, 

 however, and thereby seemed to be longer. The hybrid did not 

 hatch any of them ; but from some which were hatched by the 

 old Goose proceeded young ones, diflfering only from young Geese 

 in the rather darker colour of the feet. 



I hope that my information will be welcome to you, and 



I remain. Sir, 



Your obedient servant, 



J. P. VAN WiCKEVOORT CrOMMELIN. 



Sir, — You, like myself, have doubtless not failed to observe 

 that during the last few years our islands have been visited by 

 many species of birds whose natural habitat is the eastern por- 

 tion of the European continent and Asia. The cause of these 

 * [Cf. Ibis, 1868, p. 226.— Ed.] 



