PROCEEDINGS OF SOCIETIES. 315 



plant could advantageously possess a small uncoloured corolla, and 

 be proterogynous. Watching the mode in which wasps visited the 

 Scrophularia nodosa afforded the solution of the problem. The first 

 flower visited by the wasp w^as the top one, and it passed irregularly 

 downwards from flower to flower, and left the inflorescence by the 

 lowest flower. Bees, when collecting honey, do the reverse, visiting 

 the lowest flower first, and proceeding from flower to flower in 

 regular succession from below upwards, leaving by the top flower. 

 The order in which the flowers are visited is therefore of the greatest 

 importance. In Gladiolus, for example, the bee begins at the lowest 

 flower, and will deposit any pollen brought by it from a neigh- 

 bouring spike, and as it passes upwards it will get from the upper 

 flowers a fresh supply of pollen to apply to the lower flowers of 

 another spike. In Scrophularia nodosa wasps, which are less 

 highly speciahzed as honey collectors, chiefly visit the flowers and 

 proceed from above downwards, leaving the inflorescence with 

 pollen from the lower flowers to apply it to the stigma of the 

 proterogynous upper flow^ers. Wasps differ from bees m one 

 important point, ciz., that while bees are purely vegetable feeders, 

 wasjDs add to a vegetable diet by x^i"e}^ng largely on insects smaller 

 than themselves. Throughout the animal kingdom Carnivora are 

 endowed with keener powers of vision and scent than vegetable- 

 feeding creatures. That keenness of vision which enables a wasp 

 to descry its prey at a distance, aided by its acute sense of smell, 

 in aU probability also enables it to discover these obscure flowers, 

 without the guidance afforded by a coloured corolla, the materials 

 that would be required for its production being employed more 

 economically by the plant, just as in cleistogamic flowers. The 

 wasp also gains an advantage, as it has a better chance of finding 

 honey in these obscure flowers on account of then- being easily 

 overlooked by insects less highly endowed as regards X30wers of 

 scent and vision. — " Notes on Dimorphic Plants," by A. S. Wilson. 

 The author pomted out that Erythrcea Centaurium was probably 

 dimoi-phic, as it exhibited heterostyly, and had two kinds of pollen- 

 grains. Silene acaulis was shown to have three kinds of flowers, 

 male, female, and hermaphrodite, thus resembling S. injiata, which 

 Axel has shown to be trioeciously polygamous. — " Some Mechanical 

 Arrangements subserving Cross-fertilization of Plants by Insects," 

 by A. S. Wilson. The plants considered were Vinca miyior, Pinguicula 

 vulgaris, and the foxglove, and the author described the various 

 structural peculiarities in the different flowers. — " On the Amounts 

 of Sugar contained in the Nectar of various Flowers," by A. S. 

 Wilson. Nectar is intended to provide an inducement to cause 

 insects to visit the flowers. These insects confer great benefit on 

 the flowers by assming their cross-fertilization, bringing pollen from 

 other plants and depositing it on their stigmas. The result of this 

 is that the plant is enabled to produce seeds of much greater 

 vigour than it otherwise would. The saccharine fluid is usually 

 contained in the most secluded part of the flower, in order that it 

 may be protected from rain, for, owing to the solubihty and the 

 diffusibility of sugar, were it not so protected it would speedily be 



