io Chapters in Modern Botany CHAP. 



ledge is mainly due, have shown that there is normally a 

 considerable amount of fluid secreted by the pitcher, 

 although this does not seem to appear in European culti- 

 vation, and that this fluid has distinctly anaesthetic and 

 fatal properties to insects immersed in it. 



Other Relations to Insects. It is an odd fact that 

 while with us the bluebottle falls an easy and natural prey 

 to this unwonted trap, being doubtless attracted like the 

 wasp by that odour of decomposing carrion to which the 

 bee and butterfly in turn owe their safety, a shrewder 

 American cousin (Sarcophaga sarracenice) lays a few eggs 

 over the pitcher edge, where the maggots hatch and fatten 

 on the abundant food. In April three or four of these 

 larvae are tp be found, but in June or July only one sur- 

 vives, the victor who has devoured his brethren. But 

 nemesis is often at hand in the form of a grub-seeking 

 bird, who slits up the pitcher with his beak, and makes 

 short work of all its eatable contents. For this bird in 

 turn the naturalist has next to lie in wait, and so add a 

 new link to the chain. 



The larvae of a moth (Xanthoptera semicrocea) also 

 inhabit the pitcher, but devour its tissue, not its animal 

 inmates ; in fact, they spin a web across its diameter, as if 

 to exclude further entrance of these, and then devour the 

 upper part of the tissue, especially, it would seem, the 

 nectar-glands, finally passing through their chrysalis stage 

 within the cavity of the pitcher, and not, as in the case of 

 the Sarcophaga larva, making their exit into the ground. 



It is said that spiders also spin their webs over the 

 mouths of the pitchers and wait to reap the profit of their 

 attractiveness again a point of almost human shrewdness. 



An American entomologist, Professor Riley, has de- 

 scribed the ways in which these associated living insects 

 (commensals, we may perhaps call them, by a not extreme 



