Under this heading Mr. W. W. Bailey gives the following observations in
the current number of the _American Naturalist_:--
"The many curious observations published of late in regard to vegetable
fly-catchers have opened my eyes to such phenomena as are presented in
my forest walks. As is well known to all botanists, our sweet swamp
Azalea (Azalea viscosa) has its corolla covered on the outside with
innumerable clammy and glandular hairs. Each hair is a prolongation of
the cuticle, and is surmounted by a purple and globular band. In the bud
these hairs appear to cover the whole surface of the flower, but when
the corolla expands they are seen to occupy the midrib of the petals as
well as the tube of the corolla. These glandular hairs are efficacious
fly-catchers, but what the object is in thus securing insect prey I will
not pretend to state. I have been amusing myself, if any such
apparently cruel occupation can be considered entertaining, in watching
the capture of flies by the Azaleas. When I first brought the flowers
home, many small insects, as winged ants, were entrapped amidst the
hairs. These have remained alive several days, still vainly struggling
for freedom. As the house-flies are abundant in my room, it occurred to
me that I might extirpate the pests, and at the same time learn
something of the process of insect-catching. I have not noticed that the
powerful fragrance of the blossoms attracts the house-fly, although I
have no doubt that it does the smaller insects. It seemed to be
accidental when the house-flies were captured. I exposed a number of
buds and fully-opened blossoms on a sunny window-sill thronged with
flies. It was not many minutes before I had several captives. A mere
touch of a fly's leg to the glutinous hairs was sufficient for his
detention. A struggle only made matters worse, as other legs were by
this means brought in contact with the glands. These emit long glairy
threads, which fasten to the hairs of the flies' legs. They may be drawn
out to a great length and tenuity, still retaining their strength. If
two buds are pressed together, and then drawn apart, innumerable threads
may be seen to bind them. There is a complete network of them between
the various glands. They will confine the strongest fly; he is at once
held like Gulliver among the Lilliputians. Under the microscope the legs
of the fly are seen to be covered with the secretion, which is perfectly
white and transparent. In one attempt to escape, a house-fly lifted a
flower bodily from the window-sill, perhaps a quarter of an inch, but at
once sank back exhausted amidst the hairs. One, after long efforts,
escaped, but seemed incapable of using its legs; it flew away readily.
In one instance I have found the dried remains of a small insect
embedded amidst the hairs, but cannot say whether its juices were in any
way absorbed by the plant. If such assimilation takes place, what is its
purpose? Can this phenomenon of fly-catching be accidental, or is some
nice purpose concealed in it? I merely state the facts as I have
observed them; perhaps others can supply further information."