INSECTS IN RELATION TO PLANTS 257 
purpose of catching insects. The stout hairs of these leaves 
end each in a globular knob, which secretes a sticky fluid. 
When a fly alights on one of these leaves the hairs bend over 
and hold the insect; then a fluid analogous to the gastric juice 
of the human stomach exudes, digests the 
Fic. 250: 
albuminoid substances of the insect and 
these are absorbed into the tissues of the 
leaf; after which the tentacles unfold 
and are ready for the next insect visitor. 
The Venus’s flytrap is another well- 
known example; the trap, formed from 
the terminal portion of a leaf, consists of 
two valves, each of which bears three 
trigger-like bristles, and when these are 
touched by an insect the valves snap to- 
gether and frequently imprison the insect, 
which is eventually digested, as before. 
In the common pitcher-plants, the pitcher, 
fashioned from a leaf, is lined with down- 
ward pointing bristles, which allow an 
insect. to enter. but prevent its escape. 
The bottom of the pitcher contains water, 
in which may be found the remains 
of a great variety of insects which 
have drowned. There are even nectar 
glands and conspicuous colors, presum- 
ably to attract insects into these traps, 
Fructifying sprouts of 
where their decomposition products are a fungus, Cordyceps rave- 
nelii, arising from the 
Mineo ess eusermr tothe plant. “In \igay of. a white erub, 
I79709f90 argein of a l af rolls Lachnosterna. Slightly 
Pingu ula the m ee es : reduced.—After RILEY. 
over and envelops insects that have 
been caught by the glandular hairs of the upper surface 
of the leaf, a copious secretion digests the softer portions of 
the insects, and the dissolved nitrogenous matter is absorbed 
into the plant. Utricularia has little bladders which entrap 
small aquatic insects. These plants are only partially depend- 
18 
