INDIRECT BENEFITS DERIVED FROM INSECTS. 299 



fertilizing influence. Sprengel supposes thatVith this 

 view some plants have particular insects appropriated to 

 them, as to the dioecious nettle Catheretes Urticce, to the 

 toad-flax Catheretes gravidus, both minute beetles, &c. 

 Whether the operations of Cynips Psenes be of that 

 advantage in fertilizing the fig, which the cultivators of 

 that fruit in the East have long supposed, is doubted by 

 Hasselquist and Olivier ^, both competent observers, who 

 have been on the spot. Our own gardeners, however, 

 will admit their obligations to bees in setting their cucum- 

 bers and melons, to which they find the necessity of them- 

 selves conveying pollen from a male flower, when the 

 early season of the year precludes the assistance of in- 

 sects. Sprengel asserts, that apparently with a view to 

 prevent hybrid mixtures, insects which derive their ho- 

 ney or pollen from different plants indiscriminately, will 

 during a whole day confine their visits to that species on 

 which they first fixed in the morning, provided there be 

 a sufficient supply of it''; and the same observation was 

 long since made with respect to bees by our countryman 

 Dobbs^ 



Thus we see that the flowers which we vainly think are 



" born to blush unseen. 



And waste their fragrance on the desert air," 



though unvisited by the lord of the creation, who boasts 

 that they were made for him, have nevertheless myriads 

 of insect visitants and admirers, which, though they pil- 

 fer their sweets, contribute to their fertility. 



I am, &c. 



" Hasselquist's Travels, 253. Latr. Hist. Nat. xiii. 204. 

 " Willd. Grutuiriss, 3f)3. ' Phil. Trans, xlvi. 536. 



