ASSISTANCE OF INSECTS IN IMPREGNATION. 26S 



fig. This receptacle has only a very small orifice at the 

 summit. The seeds therefore would not in general be 

 perfected were it not for certain minute flies of the ge- 

 nus Cynips, continually fluttering from one fig to the 

 other, all covered with pollen, and depositing their eggs 

 within the cavity. 



A very curious observation is recorded by Schreber 

 and Willdenow concerning the Aristolochia Clematitis, 

 Engl. Bot. t. 398. The stamens and pistils of this flow- 

 er are enclosed in its globular base, the anthers being 

 under the stigma, and by no means commodiously situ- 

 ated for conveying their pollen to it. This therefore is 

 accomplished by an insect, the Tipula pemiicornis, which 

 enters the flower by the tubular part. But that part be- 

 ing thickly lined with inflexed hairs, though the fly en- 

 ters easily, its return is totally impeded, till the corolla 

 fades, when the hairs lie flat against the sides, and allow 

 the captive to escape. In the mean while the insect, 

 continually struggling for liberty, and pacing his prison 

 round and round, has brushed the pollen about the stig- 

 ma. I do not doubt the accuracy of this account, 

 though I have never caught the imprisoned Tipula. In- 

 deed I have never seen any fruit formed by this plant. 

 Probably for want of some insect adapted to the same 

 purpose in its own country, the American Aristolochia 

 Sipho^ though it flowers plentifully, rarely forms fruit in 

 our gardens. That it sometimes does, I have been in- 

 formed by Lady Amelia Hume, since the first edition of 

 this work was published. 



The ways in which insects serve the same purpose 

 are innumerable. These active little beings are peculiarly 



