Chap. XIII.] MANNER OF CAPTURING INSECTS. 251 



which enclose objects, such as bits of wood, cork, balls of 

 paper, or which have had their filaments merely touched, 

 and those which enclose organic bodies yielding soluble ni- 

 trogenous matter. In the former case the leaves, as we 

 have seen, open in under 24 hrs. and are then ready, even 

 before being fully expanded, to shut again. But if they 

 have closed over nitrogen-yielding bodies, they remain close- 

 ly shut for many days; and after re-expanding are torpid, 

 and never act again, or only after a considerable interval of 

 time. In four instances, leaves after catching insects never 

 re-opened, but began to wither, remaining closed in one 

 case for fifteen days over a fly; in a second, for twenty-four 

 days, though the fly was small; in a third for twenty-four 

 days over a woodlouse; and in a fourth, for thirty-five days 

 over a large Tipula. In two other cases leaves remained 

 closed for at least nine days over flies, and for how many 

 more I do not know. It should, however, be added that in 

 two instances in which very small insects had been naturally 

 caught the leaf opened as quickly as if nothing had been 

 caught; and I suppose that this was due to such small in- 

 sects not having been crushed or not having excreted any 

 animal matter, so that the glands were not excited. Small 

 angular bits of albumen and gelatine were placed at both 

 ends of three leaves, two of which remained closed for 

 thirteen and the other for twelve days. Two other leaves 

 remained closed over bits of meat for eleven days, a third 

 leaf for eight days, and a fourth (but this had been cracked 

 and injured) for only six days. Bits of cheese, or casein, 

 were placed at one end and albumen at the other end of three 

 leaves ; and the ends with the former opened after six, eight, 

 and nine days, whilst the opposite ends opened a little later. 

 None of the above bits of meat, albumen, &c., exceeded a 

 cube of -^ of an inch (2.54 mm.) in size, and were some- 

 times smaller; yet these small portions sufficed to keep the 

 leaves closed for many days. Dr. Canby informs me that 

 leaves remain shut for a longer time over insects than over 

 meat; and from what I have seen, I can well believe that 

 this is the case, especially if the insects are large. 



In all the above cases, and in many others in which leaves 

 remained closed for a long but unknown period over insects 

 naturally caught, they were more or less torpid when they 



