OF SELBOENE. 
227 
LETTER XXX. 
TO THE HONOURABLE DAINES BARRINGTON. 
Selbobne, April 3, 1776. 
ONSIEUK HEUISSANT, a French anato- 
mist, seems persuaded that he has discovered 
the reason why cuckoos do not hatch their 
own eggs : the impediment, he supposes, 
arises from the internal structure of their 
parts, which incapacitates them for incubation. According 
to this gentleman, the crop, or craw, of a cuckoo does not lie 
before the sternum at the bottom of the neck, as in poultry 
[Gallince) , pigeons [Golumbce) , &c., but immediately behind 
it, on and over the bowels, so as to make a large protuber- 
ance in the belly.^ 
Induced by this assertion, we procured a cuckoo, and 
cutting open the breast-bone and exposing the intestines 
to sight, found the crop lying as mentioned above. This 
stomach was large and round, and stuffed hard, like a pin- 
cushion, with food, which, upon nice examination, we found 
to consist of various insects, such as small scarabs, spiders, 
and dragon-flies; the last of which, as they were just 
emerging out of the aurelia state, we have seen cuckoos 
catching on the wing. Among this farrago also were to be 
seen maggots, and many seeds, which belonged either to 
gooseberries, currants, cranberries, or some such fruit; so 
that these birds apparently subsist on insects and fruits: 
nor was there the least appearance of bones, feathers, or 
fur, to support the idle notion of their being birds of prey. 
The sternum in this bird seemed to us to be remarkably 
short, between which and the anus lay the crop, or craw, 
and immediately behind that, the bowels against the back- 
bone. 
It must be allowed, as this anatomist observes, that the 
1 "Histoire de 1' Academic Royale," 1752.— G. W. 
