CuAP. 1. SECRETION OF NECTAR. 41 



with their much stronger ones, could penetrate with ease 

 the soft inner membrane of the nectaries of the above- 

 named Orchids. Dr. H. Muller is also convinced* that 

 insects puncture the thickened bases of the standard 

 petals of the Laburnum,! and perhaps the petals of 

 some other flowers, so as to obtain the included fluid. 



The various kinds of bees which I saw vi^iiting the 

 flowers of Orchis morio remained for some time with 

 their proboscides inserted into the dry neci;aries, and 

 I distinctly saw this organ in constant movement. I 

 observed the same fact with Empis in the case of 0. 

 maculata ; and on afterwards opening several of the 

 nectaries, I occasionally detected minute brown specks, 

 due as I believe to the punctures made some time 

 before by these flies. Dr. H. Miiller, who kis often 

 watched bees at work on several species of Oichis, the 

 nectaries of which do not contain any free nectar, fully 

 accepts my view. J On the other hand, Delpino still 

 maintains that Sprengel is right, and that insects are 

 continually deceived by the presence of a nectary, 

 though this contains no nectar. § His belief is founded 

 chiefly on a statement by Sprengel that insects soon 

 find out that it is of no use to visit the nectaries of 

 these orchids, as shown by their fertilising only the 



* * Die Befrnchtung,' &c. p. 235. tinct case, Damely, the presence 

 t Treviranus conliims (' Bot. of nectar in several monocotyle- 

 Zeitung,' 1863, p. 10) a statement donous plants (as described by- 

 made by Salisbury, tbat when the Ad. Brongniart in ' Bull. Soc. Bot. 

 filaments in the flowers of anotl.er de France,' torn. i. 1854, p. 75) 

 leiiuminous plant, Edwardsia, fall between the two walls '^feuillets) 

 off, or when they aie cautiously which form the divisions of the 

 separated, a large quantity of ovarium. But the nectar in this 

 sxceet fluid flows from tlie points case is conducted to the outside 

 of separation ; and as befureliaud by a channel ; and the secreting 

 there was no tiace of any such surface is homologically an ex- 

 fluid, it must have been contained, terior surface, 

 as Treviranus remarks, within the J 'Die Befruchtung,' &c. p. 84. 

 cellular tissue. I may add an ap- § 'Ult. Osservazioni sulla Di- 

 parently similar, but really die- cogamia,' 1875, p. 121. 



