HI.] CRUCIFER.-E. 57 



reach the honey, but not lap it conveniently. She, 

 however, is in the habit of biting a hole through the 

 tube, by which means she obtains access to the honey, 

 and in some plants the greater number of flowers 

 will be found to have been treated in this manner. 

 Several other bees, for instance, the hive bee, A ndrena 

 albicans, K. ; A. nitida, Fourc. ; Sphecodes gibbus, L. ; 

 and Nomada fabriciana, L., have been observed by 

 Miiller to make use of the entrance thus prepared for 

 them. Moreover, though the hive bees are unable to 

 suck the flowers in their natural condition, the flowers 

 are visited by them for the sake of their pollen. 



CRUCIFER^. 



The Wallflower, Stock, Cabbage, Shepherd's Purse, 

 Watercress, &c. belong to this group. 



The Cruciferje are easily distinguished from other 

 orders by their four sepals and petals, and six sta- 

 mens ; but the genera into which they are divided are 

 by no means so well marked, and are to a great extent 

 distinguished by differences in the pods and seeds. 

 The general structure of the flower is more or less 

 similar throughout the order, but the number and 

 position of the honey-glands differs in almost every 

 species. Hesperis matronalis is one of those plants 

 • which are specially odoriferous in the evenings, and is 

 therefore probably in most cases fertilised by moths, 

 though it is also visited by day-insects, as, for in- 

 stance, by the hive bee, the white butterflies (Pieris 

 brassiccB, P rapt, and P. napi), Halictus leucopus, 

 Andrena albicans, Volucella pellucens, Rhingia ros- 

 trata, &c. 



