510 
PSTCHE. 
UNUSUAL CARE OF ANTS FOR APHIDES. 
BY WILLIAM TRELEASE, 
Wuite collecting leaf-fungi on dAn- 
dromeda ligustrina, in asphagnum swamp 
at Wood’s Holl, Mass., in the early part 
of September 1881, my attention was 
attracted by a small, rough mass, appar- 
ently of dried sphagnum, surrounding 
one of the twigs, at a distance of about 
a metre and a half above the ground. 
Curious to know how it had reached that 
unusual place, and what it really was, 
I went to it, and on closer examination 
found it to béa shelter erected by a col- 
ony of about a dozen worker ants over 
a numerous herd of small wingless brown 
aphides, which feed on the sap of this 
plant. 
The twig on which the nest was 
placed had a diameter of about 3 mm., 
branched once at the top, and again 
at about 8 mm. from the bottom of 
the nest; between these branchlets a 
single leaf was given off. The nest 
was 3 cm. long, 1.3 em. broad at the 
largest part, near the middle, tapering 
somewhat toward each end, where it 
was quite abruptly rounded off, run- 
ning down the stem in a thin, solid layer 
for a very short distance. The wall, 
which had an average thickness of about 
0.5 mm., also ran out in the same way, 
where the branchlets passed through. 
These decurrent portions formed the only 
support of the structure, which thus 
enclosed a capacious chamber surround- 
ing the twig. On the inner surface, so 
far as seen, the wall was carefully 
smoothed off; the outer surface was 
CAMBRIDGE, MASS. 
quite irregular and rough. <A small 
round opening existed at each end. 
That at the top was 3 mm. in diameter ; 
the lower one was very minute, having 
a diameter of less than 1 mm. As I 
have said, the nest at first sight appeared 
to consist of dry bog-moss; a micro- 
scopic examination, however, showed 
the material to be chiefly small fragments 
of wood —evidently obtained from an 
old log lying at the foot of the shrub— 
with small quantities of the leaf-frag- 
ments of mosses and phaenogams. the 
whole apparently glued together by the 
saliva of the ants. 
At first, neither ants nor aphides were 
visible, but on jarring the plant slightly, 
I saw the head of an ant protruded from 
the larger entrance, the antennae of 
another appearing simultaneously at the 
smailer. With the point of a penknife 
I now enlarged the latter opening, upon 
which several ants rushed out furiously, 
and two or three swarmed upon my fin- 
ger which was in contact with the twig, 
trying to bite and sting it. The ant at 
the upper opening also came out, fol- 
lowed by one or two others, but these 
apparently failed to locate the distur- 
bance, and soon reéntered the nest, as 
did those from below which had not 
touched my finger. Those upon my fin- 
ger were not allowed to return to the 
nest, and the excitement was of short 
duration. Through the enlarged opening, 
which was from time to time curiously 
examined by some of the ants, I could 
