184 Jcmrnal of Travel and Natural History 



the honey in the nectary may be a bait by which the presence of 

 insects is secured is not open to any objection on the score of in- 

 sufficiency or unsuitableness of the means employed. The ob- 

 jection is of another character. It is the error of supposing that 

 the hypothesis is not only a true explanation of the facts observed, 

 but that it is the only one, and that it applies to all cases. Signor 

 Delpino's observations, however, extend over a large number 

 of species of various orders of plants ; and whether the reader 

 adopts his views to their full extent or not he will find in 

 his paper a great deal of interesting information as to different 

 contrivances and apparatus which in many cases it seems scarcely 

 possible to deny have fecundation by insects for their purpose. 



Of the Leguminosae, which those who deny the necessity of the 

 intervention of insects in the fecundation of flowers are fond of 

 citing in support of their views, he gives the following as the 

 different ways in which the fecundation in them is effected by 

 means of insects, first premising that the constant occurrence of a 

 nectary at the base of the insertion of the isolated stamen was in 

 itself sufficient proof to him that fecundation must be effected by 

 that means : the existence of nectaries being, according to him, 

 solely for this use. He found the plan of the apparatus for fecund- 

 ation reducible to four types. In all four it is the keel which plays 

 the principal part, and, consequently, his observations can only 

 apply to those Leguminosae which have a keel. In the commonest 

 type the keel enveloped in the wings forms as it were a guard to 

 the stamens and stigma. A hymenopterous insect comes to place 

 itself on the flower. The introduction of its proboscis to suck the 

 honey causes the keel to diverge from its proper position. It 

 yields, and in yielding lays bare the anthers and stigma, which 

 thus rub against the back and abdomen of the insects, the anthers 

 abandoning their own pollen, and the stigmas agglutinating a por- 

 tion of that already attached which had been taken from flowers 

 previously visited. We have not space to pursue the contrivances 

 exhibited in the other three phases. The reader may trace them 

 for himself in Lotus corniculatus, which is the type of the second 

 phase, .in Phaseolus caracalla, which is the type of the third, and 

 in the species of the genus Medicago (M. sativa, M. arborea, &c.), 

 which is the type of the fourth phase. 



The general impression left on our minds by perusal of Signor 

 Delpino's paper is that while he is probably right in considering 

 much of the apparatus he describes as special contrivances for 



