HYMENOPTERA—BEES 157 



If the cardines (c) now rotate forwards again, the entire suctorial apparatus is 

 carried forwards by twice the length of these structures. The retractors (2) next 

 rotate forwards, and a further advance of twice their length' is given to the mentum 

 {mi) with its appendages (labial palps and ligula), while the maxillae remain in their 

 place, and their laciniae enclose only the mentum and posterior part of the li^uIa. 

 Finally, the basal part of the ligula, contained in the hollow end of the mentum, 

 is protruded and its tip attains the maximum extension (e.g. in Bombus hortorum, 

 20 to 21 mm. beyond the mouth) and dips again into the nectar at the base of the 

 flower-tube. 



In flowers rich in nectar, a humble-bee may be seen to perform the act of 

 sucking four or five, or sometimes even eight or ten times, the tip of the ligula 

 being apparently dipped into the nectar, drawn back into its sheath, and the sheath 

 drawn up to the mouth, for the same number of times. 



2. To reach honey which is less deeply situated the bee need not rotate 

 the retractors forwards. They remain directed backwards, so that the ligula is 

 constantly ensheathed by the lacinia and labial palps, only its base moving in and 

 out, so that, alternately, its tip wet with nectar is retracted into the suctorial tube, 

 and after discharging its load is again protruded. 



3. When the bee flies from flower to flower in search of nectar, it carries the 

 suctorial organ (' proboscis ') extended, so as to introduce it, while in the act of 

 alighting, into the opening of a flower ; but the ligula is completely concealed 

 between the laciniae and the labial palps, so that the delicate whorls of hair are 

 protected during the act of insertion into a flower-tube, while at the same time 

 the terminal joints of the labial palps are able to perform their tactile function. 

 In flying from flower to flower the base of the ligula is therefore contained within 

 the hollow end of the mentum, and the retractors are directed .backwards, while 

 the cardines may be directed vertically downwards (Fig. 67), or forwards (Fig. 66, 2), 

 or backwards, according to the depth of the flower which the bee has in view. 



4. The mouth-parts must assume exactly the same position when the bee bores 

 into delicate tissues with the sharp points of its laciniae, whether to get at the sap 

 (as, for example, during visits to our meadow orchids, which do not secrete free nectar) 

 or to suck deeply seated nectar through the hole, as in the case of Bombus terrester, 

 when it visits meadow clover and many other long-tubed flowers. 



5. In collecting pollen, the honey-bee and humble-bee use their mouth-parts 

 in two different ways to moisten it, according as it is the adherent pollen of ento- 

 mophilous flowers, or the loose and easily scattered pollen of anemophilous flowers. 

 In the former case (e.g. when the honey-bee collects pollen on willow catkins) the 

 suctorial apparatus is completely folded downwards (as in Fig. 69), and the bee 

 brings its mouth (which lies between the labrum and the base of the mandibles) 



the author, the following remarks are added to the footnote : — ' At the same time, special muscles for 

 the erection of the whorls are not present ; and therefore my explanation becomes unsatisfactory. 

 In several Brazilian bees, my brother, Fritz Miiller, has found that the hairs of the tongue are 

 transformed into stalked scales, which seem hardly fitted to drive the honey mouthwards by erection. 

 In an undescribed azure-bine Euglossa, the imbricated scales seem to form a tnbe round the tip of 

 the tongue, so that here suction may perhaps go on without the tip of the tongue being withdrawn 

 into the sheath formed by the laminae [laciniae] and labial palps.' — Tr.] 



