12 TRANSACTIONS OF THE [OCT. 17, 



fitted to tliG jOfroniKT is destitute of marf^inal spikes. Second, 

 the elustre of radial leaves is admirably disposed in ]X)sition 

 and succession * to cover accurately tLe extent of allotted 

 gi'ound. Third, the leafy petioles present a well designed run- 

 way, passing from cential biid to tra]\ which an insect is more 

 than apt to follow as a method of escape, after it has run the 

 gauntlet of trapping leaves. 



The actual disposition of the trap when, so to say, set, may 

 thus be stated. The leafy petiole sprouts boUlly upward, then 

 descends gradually towards the trap. At first its face is narrow 

 and fiat, then its leafy margins begin to spread out laterally 

 more and more until the trap is reached ; these leaf}' margins 

 bend upward, often curling over, and thus form a creased run- 

 way, admirably fitted to keep a visiting insect in the broad de- 

 scending path. The leaf-stalk is decidedly spring}- it its back- 

 ward curve, so much so that if its base be severed it writhes 

 backward describing normally a curve of about 200°. Irri- 

 tation of the stalk may thereafter cause the total flexure to 

 become about 400°. This remarkable springiness appears to 

 bring with it three important functions, (1) it causes the outer 

 margin of the trap to be closely pressed to the ground — a 

 position that is accommodated by the lamino-peliolar hinge, (2) 

 it steepens the final descent of the runway, tending to prevent 

 the retreat of visitors, and (3) it hel]5s to adjust with nicety the 

 leafy edges of the petiole to the sides of the trap and prevents 

 intei'stical escapes, f The ascending portion of the runway 

 has been carefully examined for aids to climbers, but these do 

 not apparently occur. There are no hairs even along the mar- 

 gins, the ascent is smooth, a bit vascular, a condition i)erhaps 

 of advantage to the padded feet of visitors. This moistness is 

 somewhat viscid, judging from the dust and minute granules 

 usually adherent. The trap itself in its disposition appears to 

 be singularly adapted to its environment, not mei-ely in the 

 degree in which it opens lint in the concavity of its lobes and in 

 the bend of its marginal s^nkes. In the position commonly 

 assumed the tip of the trap rests upon the ground, the lobes 

 arc^oing slightly upward are inclined to each other at an angle 

 of about 50°, their concavity is well marked, the spikes inclin- 

 ing slightly inward. This position appears to be the one of 



* C. F. Lubbock, Loaves. Flowers aTid Fniits, in rosard to leaf disposition for 

 other functions, e. g., respiration. 



t The position of the trap, the decree to wiiich it is open, the amonnt of iiond- 

 ing of ttio joint, seem to delermiiio tlie ni'-ety of tlie adiiistnieiit of llie springy 

 margins— tiiese, when the angle lictwpen petiole and iilade, liecnmes marked, Jire 

 usually closely opposed to the inner face of the trap, often in this way forniii'.g 

 a kind of leafy funin-l, 



