6 STRUCTURE OF THE LEPIDOPTERA 



antennae of butterflies are always straight, or only slightly curved ; 

 and, although the insects can sway them bodily, they have no 

 power to bend them, or to stow them away in any place of shelter. 

 Moths, on the other hand, when at rest, are almost invariably found 

 to have their antennae snugly tucked under the wings, and brought 

 so closely against the side of the head for this purpose that even 

 the uncovered portion is often difficult to find. 



There are two other prominent appendages belonging to the 

 heads of the Le2ndoptera. These are the labial palpi or feelers of 

 the lips. They are generally easily seen, projecting forward on the 

 under side of the head, sometimes so long and conspicuous as to 

 give one the idea of a snout or long nose. The palpi are jointed 

 usually in three parts are covered with scales, and often furnished 

 with hairs or bristles. 



If you watch a moth or butterfly when it is feeding on the 

 sweet juices of a flower, or on some kind of artificial sweet with 

 which you have provided it, you will observe its long trunk or pro- 

 boscis, by which food is sucked up. This instrument is so long and 

 slender that it seems almost impossible that it can be a tube 

 through which a liquid freely passes. But a careful examination 

 will show that this is the case. It is composed of two separate 

 pieces two half tubes, which, when closely applied to each other, 

 form a very thin and flexible pipe, perfectly air-tight and adapted 

 for suction. Sometimes you can see a butterfly or moth manipu- 

 lating with its proboscis as if it required readjustment in some way 

 or other. It has split the tube throughout its length, so that it now 

 looks like two exceedingly fine hairs. Then, after a short time, the 

 two halves are put together again, and immediately, as if by magic, 

 become a single tube in which no kind of seam is to be observed 

 without a powerful magnifier. 



In order to observe the nature of such a wonderful arrangement 

 we must have recourse to the aid of a good microscope. Thus 

 assisted, we can see at once how the junction of the two sides of 

 the proboscis is brought about so quickly and so perfectly. The 

 inner edges of each half are very regularly fringed with lines of 

 closely set hairs so regular, in fact, are they, that they give one 

 the idea of long yet minute beautifully formed combs. When the 

 two parts are brought together, the hairs of two opposite edges 

 interlock, those on one side exactly filling the spaces between those 

 of the other. 



The microscope also reveals another interesting fact, viz. that 



