Cuarp. XIIL] MANNER OF CAPTURING INSECTS. 247 
On the Manner in which Insects are caught.—We will now 
consider the action of the leaves when insects happen to 
touch one of the sensitive filaments. This often occurred in 
my greenhouse, but I do not know whether insects are 
attracted in any special way by the leaves. They are caught 
in large numbers by the plant in its native country. As 
soon as a filament is touched, both close with astonishing 
quickness ; and as they stand at less than a right angle to 
cach other, they have a good chance of catching any intruder. 
The angle between the blade and footstalk does not 
change when the lobes close. The chief seat of movement is 
near the midrib, but is not confined to this part; for, as the 
lobes come together, each curves inwards across its whole 
breadth ; the marginal spikes, however, not becoming curved.* 
This movement of the whole lobe was well seen in a leaf to 
which a large fly had been given, and from which a large 
portion had been cut off the end of one lobe; so that the 
opposite lobe, meeting with no risistance in this part, went 
on curving inwards much beyond the medial line. The 
whole of the lobe, from which a portion had been cut, was 
afterwards removed, and the opposite lobe now curled 
completely over, passing through an angle of from 120° to 
130°, so as to occupy a position almost at right angles to 
that which it would have held had the opposite lobe been 
present. 
From the curving inwards of the two lobes, as they 
move towards each other, the straight marginal spikes inter- 
cross by their tips at first, and ultimately by their bases. 
The leaf is then completely shut and encloses a shallow 
cavity. If it has been made to shut merely by one of the 
sensitive filaments having been touched, or if it includes an 
object not yielding soluble nitrogenous matter, the two lobes 
retain their inwardly concave form until they re-expand. 
The re-expansion under these circumstances—that is when 
no organic matter is enclosed—was observed in ten cases. 
In all of these, the leaves re-expanded to about two-thirds 
of the full extent in 24 hrs. from the time of closure. Even 
the leaf from which a portion of one lobe had been cut off 
opened to a slight degree within this same time. In one 
* (Munk (Reichert and Du Bois’- at the edge of the leaf, by which the 
Reymond’s ‘Archiv,’ 1876, p. 108) teeth are carried inwards.—F. D.] 
states that a special movement occurs 
ee) 
