60 



THE AQUARIUM, JULY, 1893. 



late investigation, and is now a definitely 

 settled fact. The first intelligent de- 

 scription of these rooted 'Fra Diavolos' 

 was forwarded by the naturalist Ellis, 

 in a letter to Linne about 1768. He 

 had one of these brutal plants sent to 

 him from the swamps of Carolina, so 

 that he could himself observe these 

 habits of trapjiing its game. He 

 described this bandit in about the fol- 

 lowing manner : The plant sends out 

 of a peculiar shaped leaf rosette a spike 

 of flowers of a beautiful white color. 

 This plant Ellis named (Dionea nius- 

 cipula) Venus' fly-trap, which name 

 Linne also adopted. The margin of 

 the leaf is encirled by small delicate 

 bristles, and on the ujiper surface of 

 each half of the leaf three to four of 

 these sharp bristles are also found. 

 Between these last are found glands 

 which secrete a reddish, viscid fluid, by 

 means of which the insects are induced 

 to venture on this dangerous parquette. 

 The instant this occurs the two halves 

 of the leaf close, the marginal bristles 

 close over the edges like the hands 

 clasped in prayer, the force being so 

 great that the leaf becomes torn, if the 

 effort to open it is persisted in. Ellis 

 asserts that the insect is imi^aled on the 

 central bristles, not unlike the victims 

 of the middle ages, being inclosed in 

 the machines of torture. This idea of 

 impalement was erroneous and Linne 

 seems to have considered the whole let- 

 ter as such, he refused to accept the 

 theory of digestion, of which Ellis had 

 hinted. He (Linne) considered Venus' 

 fly-trap as a new species of the Sin-plant 

 and therefore reasoned, the leaf only 

 remained closed as long as the irritation 

 was kept up, when it would again open, 

 without having utilized the cadaver. 



Already Ellis had noticed that by 

 irritating the upper surface of the leaf 



with a needle or piece of straw, it 

 would close, but on perceiving it had 

 no insect inclosed, would soon unfold 

 itself, while this does not occur when 

 an insect is caught. Linne held to his 

 belief. Only the elder Darwin con- 

 cluded there must be some use for this 

 system of preying, and thought that 

 the flower was surrounded by the leaves 

 to prevent insects from making their 

 ascent to th-e flowers and there causing 

 destruction. The son of Darwin, next 

 to the German botanists, Sprengle and 

 Miller, has given the clearest explana- 

 tion of this habit of catching insects by 

 these plants. The bright colors and exu- 

 dation of the honey-like substance would 

 exclude the idea of j^i'otection, more 

 readily serving the purpose of a bait. 



AYe often see illustrations of spiral 

 plants, with heart-shaped leaves and a 

 tube-like flower. This is the common 

 snake root (Aristolochia clematatis), the 

 flowers of which to a certain degree re- 

 semble a mouse trap. The mouth of 

 the flower is covered with stiff hair, the 

 points of which are directed to the in- 

 terior, allowing an insect to readily find 

 entrance to the interior of the flowei', 

 but with difficulty making its exit. 

 This does not occur before it has de* 

 posited the pollendust brought from 

 some other plant and has again taken 

 up some new in place of that deposited, 

 when the hair will become smooth with 

 the body of the blossom, allowing of an 

 easy exit, the insect now being free, 

 leaves, soon to fall into a new trap, 

 there again to perform the same duties. 



Before the investigations of Darwin 

 it was thought that these arrangements 

 of Venus' fly-trap were of no use to the 

 plant. Dr. Curtis, of Wilmington, 

 N. C, in 1834 noticed that the dead in- 

 sects became dissolved in the exudation 

 of the leaves and finally disappeared. 



