262 BUTTERFLIES 



ants that feea upon the honey-dew which passes through 

 their bodies. In many cases the ants have been observed 

 to stroke the aphids with their antennae in a way which 

 seems to induce the aphid to give out a drop of the sweet 

 liquid for the ant to lap up. In a similar way these ants 

 seem sometimes to stroke these little caterpillars with their 

 antennae and thus to induce them to turn their little 

 pockets inside out with the drop of liquid at the tip. This 

 is certainly an unusual and most interesting relation be- 

 tween two insects far separated by their structural char- 

 acters. 



The little pocket that I have thus described is situated 

 upon the seventh segment of the abdomen. Just back of 

 it there are two other openings which are even more 

 curious in their structure. These are provided with some 

 slender tentacles on which there are circles of hairy spurs. 

 These structures are a great puzzle to naturalists. It is 

 difficult to explain what they are for unless we assume that 

 they relate in some way to the honey-dew pocket on the 

 seventh ring. The only plausible explanation is that these 

 serve to advertise to the ants, by giving off a distinctive 

 odor, that there is nectar near at hand to be had for the 

 asking. They would thus be analagous in a way to the 

 fragrant scent of flowers which is for the purpose of ad- 

 vertising to the bee the fact that nectar or pollen or both 

 are near at hand and may be had for the asking. In the 

 case of these caterpillars, however, if this is the true ex- 

 planation it is a most wonderful provision and one which 

 would be likely to tax the ingenuity of man's mind for a 

 long while before it was originated. 



So this little butterfly which greets us in every spring, 

 like "a violet afloat," to quote Mr. Scudder's happy phrase. 



