294 INDIRECT BENEFITS DERIVED FROM INSECTS. 



leaves of this and similar plants enter into them volunta- 

 rily ; but Sir James Smith mentions a curious fact, from 

 which it appears that in some cases they are deposited 

 by other species. One of the gardeners of the Liver- 

 pool Botanic Garden observed an insect, from the de- 

 scription one of the Sphegiadce {Sphex^ L.), which 

 dragged several large flies to the Sarracenia adunca, 

 and, having with some difficulty forced them under the 

 lid or cover of its leaf, deposited them in its tubular 

 part which Avas half filled with water : and on exami- 

 nation all the leaves were found crowded with dead or 

 drowning flies'*. What was the object of this singular 

 manoeuvre does not seem very obvious. At the first 

 glance one might suppose that, having deposited an egg- 

 in the fly, it intended to avail itself of the tube of the 

 leaf instead of a burrow. Yet we know of no such 

 strange deviation from natural instinct, which would 

 be the more remarkable because the insect was Euro- 

 pean, while the plant was American and growing in a 

 hot-house. And at any rate it does not seem very likely 

 that the insect would commit her egg to the tube with- 

 out having previously examined it ; in which case she 

 must have discovered it to be half full of water, and 

 consequently unfit for her purpose. — It is not so won- 

 derful that many large flies should, as Professor Bar- 

 ton informs us, drop their eggs into the Ascidia fur- 

 nished with dead carcases : and it seems very probable 

 that Dytisci oviposit in them ; for the Squilla which 

 Rumphius found there was probably one of their larvae, 

 this being the old , ame for them*". 



However problematical the agency of insects caught 

 » Smith's Introduction to Botany, 195. " Mouffet, 319. 



