Pedicularis and Melampyrum. 7 7 



fig. 50. In this flower a groove, bordered on either 

 side by a swelling, runs along the median line of the 

 lower lip. The humble-bees which visit the flower must 

 pass their proboscis down this groove, if their visit is to 

 be of any use ; for it is only by attacking the nectar in 

 this manner that they can cause the upper lip to incline 

 forward with a peculiar angular motion, rendered pos- 

 sible by a pair of lateral joints ; in which case the 

 powdery pollen wUl fall out of the anthers, and the 

 concealed stigma be brought down on the back of the 

 bee. Should the bee insert its proboscis higher up, 

 above the groove, the angular motion would not occur, 

 and the mechanism would not be brought into play. In 

 order, however, that the humble-bees may not so act, 

 but may be compelled to introduce their proboscis by 

 the only way which can benefit the flower, the upper 

 lip is in this region studded with small sharp teeth ; all 

 contact between which and their proboscis the humble- 

 bees have good reason to shun. 



The several species of Melampyrum present a pre- 

 cisely analogous arrangement in their flowers. As, 

 however, may be seen in Plate II. fig. 71, which 

 represents a flower of Melampyrum pratense L., the 

 pricklets are now set not on the corolla, but on the 

 filaments of the anthers, which enclose the entrance 

 to the nectariferous recess like a frame or a pair of 

 toothed jaws. Their purport, however, is precisely the 

 same as in Leonurus or in the above-mentioned species 



