216 THE ORCHID REVIEW. [JuLy, 1908- 
similar object), it immediately begins to close up, gently at first, but after- 
wards quickly, ultimately closing almost with a snap. There is then only 
a small opening, immediately in front of the anther, through which the 
insect can escape, and in so doing it would bring away the pollinia, and 
when the process was repeated on another flower, the pollinia would be left 
on the stigma. The lip closes up naturally at night, so as to protect the 
pollinia when the proper insects are not on the wing. It should also be 
added that the peduncle is protected all over by bristles (hence the name 
muscosa), which prevents useless insects from climbing up to the flower 
some other way. 
In the large Australian terrestrial genus Pterostylis the lip is also 
sensitive, and the details have been described by Fitzgerald. In P. longi- 
folia the lip is flattish and very hairy, and is attached at the base by a short 
band in front of the column, enabling it to reflex on to the lateral sepals, 
but on the slightest touch it springs up and continues to close the flower 
from half an hour to an hour and a half, according to the state of the plant 
and of the weather. It then drops down again, taking from one to five 
minutes to descend spasmodically, when after about one minute it regains 
its sensitiveness. Coming to the conclusion that the flowers were fertilised 
by small insects, Fitzgerald procured a few small beetles, and carefully 
dropped one of them on to the lip, when it was instantly carried into the 
flower, and its efforts to escape were anxiously watched for a quarter of an 
hour, when it managed to get out by creeping past the anther. It was 
then captured, and two of the pollen masses were found attached to it. The 
insect was then dropped into a flower of Pterostylis obtusa from which the 
pollinia had been removed, and a full capsule of hybrid seed was the result. 
If the plants are kept under a bell glass, no seed is ever produced. — Small 
dipterous flies, however, he thinks are the natural fertilising agents, as they 
are frequently found in the flowers of this genus, attached to the rostellum 
or to the stigma, from which they have been unable to free themselves. 
And spiders seem to be aware of the fact, for he remarks that on one 
occasion he had the good fortune to find a fly caught in a spider’s web 
which had been spread over a group of P. obtusa, and to the head of this 
little fly pollen masses of a Pterostylis were firmly adhering. The genus 
contains upwards of forty species, and exhibits great variation, and various 
degrees of sensitiveness, and in two or three cases the lip does not jump uP 
when touched. 
A reception of another kind is provided for the fertilising insect in the 
case of the Tropical American genus Coryanthes (C. macrantha was now 
thrown on the screen), for they are precipitated into a kind of cold bath, 
from which they can only escape by crawling through a small opening, 
which, as in the preceding case, results in the fertilisation of the flower- 
