184 The American Naturalist. (February, a 
ered it during the early autumn. To all appearances the plant is 
self-seeded, and is remote from any garden or cultivated ground. The 
only other vegetation in the vicinity is short stunted grass, so that the 
bush in spite of its small size, is a conspicuous object and has probably 
only escaped destruction by reason of its sharp prickly foliage. The 
locality is strikingly similar to the “commons” or “downs” where it 
grows in Great Britain. How it came here is a mystery, as the only 
other place where it is known to occur in America, so far as I am 
aware, is on the Island of Nantucket, where it was introduced about : 
1860, and has since spread to some extent. If protected and encour- 7 
aged it would doubtless become established here and spread as it has 
done in the latter locality. 
Mr. William T. Davis exhibited Cecropia cocoons which had been 
partly destroyed by woodpeckers, and read the following paper on 
woodpeckers and cecropia cocoons. 
The caterpillars of the Ceeropia moth spin their cocoons in a variety 
of places; occasionally on the flat side of a board fence, sometimes at : 
the base of bushes such as the elder, and sometimes at the ends of sway- a 
ing branches when the food plant happens to be a tree. The cocoons 
spun near the ground are often devoured by mice that gnaw through 
the silken coats to the edible pupa within. Specimens,which had been 
thus destroyed were shown to this Association by Mr. Joseph C. 
Thompson on Dec. 12, 1889. Cocoons that are placed on tree branches 
are more safe from the attacks of mice, but are liable to be eaten by 
woodpeckers. 
On January 14, 1888, I saw a downy woodpecker investigating a 
Cecropia cocoon in a white maple, the woodpecker thrusting its bill i 
and pulling it out of the cocoon quite frequently. After a while it 
flew to another cocoon a few feet away, but it being on such a small 
branch it was unable to successfully pick it open, as the branch swayed — 
up and down. It was then plain what a great protection it was to the — 
insects to place their cocoons near the branch ends, though no doubt | 
they are sometimes killed by the swaying of these branches during & 
storm. ; L 
_ When the woodpecker was gone I cut the cocoon off and found a — 
small hole on its side quite near the branch, where it was easiest to $ 
drill because the silken fabric gave way the least to the strokes of the 
bird. Cutting open the other side of the cocoon, I found that the pup# 
shell was sucked nearly dry of its contents. A 
