Xliv JOURNAL OF PROCEEDIXGS. 



by gnawing entirely round the stems of lilacs and other plants, at a 

 short distance below the surface of the ground. Also a drawing of 

 the larva of one of the StaphylinidtE, which feeds upon turnips, giving 

 them what is termed a grubbed appearance. 



He also exhibited a series of specimens illustrative of the gradual 

 development of a new species of the crustaceous genus Porcellana, 

 discovered on the coast of Hastings by W. Hailstone, junior, Esq., 

 some of which were scarcely larger than a good-sized pin's head. 



The following Memoirs were read : 



" R,emarks on some mechanical peculiarities noticed in a Spider's 

 Web at Wandsworth." By W. W. Saunders, Esq., F.L.S., &c. 

 (See p. 127.) 



" Description of Chelepteryx Collesi." By G. R. Gray, Esq., 

 M.E.S., (seep. 121,) who exhibited specimens of the insect from the 

 collection of Mrs. Children. 



" On the agency of Insects in causing Sterility in Flowers by the 

 removal of the masculine organs, observed amongst the Asclejriadece." 

 By M. Ch. Morren, communicated by M. Emilien De Wael, and 

 extracted from the ' Horticulteur Beige.' 



In this Memoir the author details a series of observations, proving 

 the generally received opinion that insects are ordinarily serviceable 

 whilst collecting the nectar of flowers, in causing their impregnation 

 by transporting the pollen from an anther to a pistil, (a fact also ob- 

 served by Labillardiere in the humming-birds,) is not without excep- 

 tion. He first cites an observation of Plenck (Physiol, des Plantes, 

 1802, 8vo, p. 206), that one of the causes of sterility in plants is pro- 

 duced by insects devouring the flower, or by the eggs being deposited 

 in the pistils, the young larvae finding their way into the fruit, and 

 causing it to ripen sooner than the uninjured fruit, but at the same 

 time to fall prematurely to the ground. He then shows, from re- 

 marks of Sennebier (Phys. Veget., vol. i. p. 335,) and Koelruter, 

 that flowers are provided with a supply of pollen far greater than is 

 necessary to fecundate the flower ; thus in each stamen of Hibis- 

 cus syriacus 4863 grains of pollen were found, whilst 50 or 60 will 

 sufiice to render the flower fertile, the remainder being scattered 

 by the wind or devoured by insects. He next cites a passage from 

 Huber (Trans. Linn. Soc. Lond., vol. vi.) concerning the gathering 

 of pollen by bees on the hind legs, whilst it is the pollen which is 

 found in their second stomach which serves for the support of them- 

 selves and their larvae. The Aiithreni, in like manner, by frequent- 

 ing flowers, scatter the pollen which may accidently rest upon the 

 pistil. The discovery of insects, however, bearing pollen, is of very 

 rare occurrence, except in the case of the bees, a circumstance ex- 



