$6 PERIOD III. 



given. He tells us that all moths have not an effective 

 proboscis, though he does not explain how some of 

 them can dispense with what seems so necessary an 

 organ ; this omission has been made good by later 

 entomologists. The proboscis, he goes on, springs 

 from the head, just between the compound eyes. When 

 at rest, it takes up very little room, for it is spirally 

 rolled, like a watch spring ; in some cases it makes as 

 few as one and a half or two turns, in others as many 

 as eight or ten ; the base is often concealed by a pair of 

 hairy palps, which serve as feelers. Careful study of a 

 moth as she flits from flower to flower shows that she 

 alights on the plant, unrolls her proboscis, passes it into 

 the corolla, withdraws it, perhaps coils it for an instant, 

 and then plunges it again into the tube. When this 

 manoeuvre has been repeated several times, the moth 

 flies off to another flower. 



Some moths have a tape-like proboscis ; in others it 

 is cylindrical. It can be made to protrude by gentle 

 pressure on the head, or be unrolled by a pin passed 

 into the centre of the spire ; it is composed of innumer- 

 able joints, and tapers from the base to the tip. When 

 forcibly unrolled, it often splits lengthwise into halves. 

 At the time of escape from the chrysalis the halves are 

 always free, and they require careful adjustment in 

 order that a continuous sucking-tube may be obtained. 

 A newly emerged moth may be seen to roll and unroll 

 its proboscis repeatedly, until at last the halves cohere 

 in the proper position. Sometimes they begin to dry 

 before the operation is completed, the half-tubes get 

 curled, and then the unfortunate moth becomes 

 incapable of feeding at all. Each half is a demi-canal, 

 whose meeting edges interlock by minute hooks. The 

 mechanism reminds Reaumur of that which connects 



