812 DIONJ^A MUSC/rULA. CUAP. XIIL 



creasing darkness ; and one of my sons actually saw a 

 small insect thus escaping. A moderately large in- 

 sect, on the other hand, if it tries to escape between 

 the bars will surely be pushed back again into its 

 horrid prison with closing walls, for the spikes con- 

 tinue to cross more and more until the edges of the 

 lobes come into contact. A very strong insect, how- 

 ever, would be able to free itself, and Mrs. Treat saw 

 this effected by a rose-chafer (Nacrodactylus subspi- 

 nosus) in the United States. Now it would manifestly 

 be a great disadvantage to the plant to waste many 

 days in remaining clasped over a minute insect, and 

 several additional days or weeks in afterwards re- 

 covering its sensibility ; inasmuch as a minute insect 

 would afford but little nutriment. It would be 

 far better for the plant to wait for a time until a 

 moderately large insect was captured, and to allow all 

 the little ones to escape ; and this advantage is 

 secured by the slowly intercrossing marginal spikes, 

 which act like the large meshes of a fishing-net, 

 allowing the small and useless fry to escape. 



As I was anxious to know whether this view was 

 correct and as it seems a good illustration of how 

 cautious we ought to be in assuming, as I had done 

 with respect to the marginal spikes, that any fully 

 developed structure is useless I applied to Dr. Canby. 

 He visited the native site of the plant, early in the 

 season, before the leaves had grown to their full size, 

 and sent me fourteen leaves, containing naturally 

 captured insects. Four of these had caught rather 

 small insects, viz. three of them ants, and the fourth 

 a rather small fly, but the other ten had all caught 

 large insects, namely, five elaters, two chrysomelas, 

 a curculio, a thick and broad spider, and a scolo- 

 pendra. Out of these ten insects, no less than eight 



