158 



INTRODUCTION 



close over the pollen. It then ejects a little honey on the pollen, takes it up by 

 means of the tarsal brushes, and places it in the baskets on the tibiae of the hind-legs. 

 The mandibles are often used to loosen the pollen before it is moistened with honey. 

 In the case of anemophilous flowers (observed and described in Plantago lanceolata 

 by Hermann Miiller) the bee, hovering before the flower, ejects a little honey upon 

 the stamens from its suctorial tube, which is fully extended, but completely sheathes 

 the ligula. Here, therefore, as when flying to suck flowers or when boring into 

 soft tissues, the base of the ligula is contained within the hollow end of the mentum, 

 and the retractors are directed backwards. Since honey-bees and humble-bees 

 when visiting entomophilous flowers extend the proboscis to suck nectar and fold 

 it up to collect pollen, while on nectarless anemophilous flowers they obviously only 

 gather pollen, it follows that they are never able to suck nectar and collect pollen 



simultaneously. They must 

 always do first one, and 

 then the other, and since 

 the pollen has to be 

 moistened with honey, 

 the act of sucking must 

 always be the first. 



On the other hand, 

 all bees that gather dry 

 pollen among a dense 

 growth of feathery collect- 

 ing-hairs are able, so far 

 as the structure of the 

 flower permits, to accumu- 

 late pollen and suck nectar 

 at the same time, and 

 they perform the latter 

 action in exactly the same 

 way as honey-bees and 

 humble-bees. It is obvious 

 that bees with an abdo- 

 minal collecting-apparatus 

 can most easily perform 

 both acts simultaneously on flowers which present their pollen from below. 



6. In order, lastly, to bring the mouth-parts to a resting position, or to use 

 the mandibles, the bee brings into action simultaneously all the four folding move- 

 ments of which its proboscis is capable. It draws back the base of the ligula into 

 the hollow end of the mentum (as in Fig. 68), folds the ligula, together with the 

 ensheathing laciniae and labial palps, downwards and backwards (Fig. 68 shows 

 the beginning of this action), rotates the retractors (2) backwards (half completed 

 in Fig. 68), and rotates the cardines (c) (which in Fig. 68 are still directed obliquely 

 forward) backwards upon their bases. The entire suctorial apparatus is thus folded 

 up and retracted into the cavity in the under-side of the head, which it completely 

 fills (Fig. 69, i). 



Fig. 68. Suctorial apparatus of Bonibtis sylvarum^ Z., ha! f folded 

 up ; seen from tlie side (after Herm. MuUer). The outer wall of the hollow 

 tip of the mentum is broken away to show the involution of the proximal 

 part of the ligula, a be: a, base of the ligula; 5, angle of the fold; abc^ 

 part of ligula folded into the hollow mentum. Other references as in Fig. 64. 



