Galeopsis. 115 



which is from 8 to 10 mm. in thickness/between the 

 upper and lower lips into the wider throat, and thence 

 pass its trunk down the remaining narrow part of the 

 tube to the nectar. But the limb of the corolla admits 

 a considerable amount of dilatation when vigorously 

 pushed. For its junction with the tube is marked 

 above by a transverse bulging line, which forms the 

 axis of a joint on which the upper Up can move up and 

 down. No sooner does a humble-bee thrust its head 

 in at the mouth of the flower than the upper lip is 

 raised like a lid, and with it of course the underlying 

 elastic and flexible filaments, as also the style. Conse- 

 quently the humble-bee comes unavoidably into suc- 

 cessive contact with the stigma and the pollen, 

 which is stored up in the protected anthers. As to 

 the smaller flying insects, all such as are not more 

 than 2'5 in thickness, can steal in at the centre 

 of the outer opening, make their way thence to the 

 funnel-shaped expansion of the tube, and, finding there 

 no "weel" nor similar obstacle to stop them, can 

 carry off the nectar from the lower and narrower part 

 of the tube; and all this without any necessity of 

 raising the upper lip, an act which would indeed be 

 beyond , their strength. If, however, its body be but 

 2'5 mm. in thickness, the insect is large enough, 

 supposing only that it makes its entrance by pass- 

 ing over the middle lobe of the lower lip, to rub 

 against stigma' and anthers, and thus, as it flies from 



