PAPILIONINAE : LAKUTIAS PHILEXOR. 1249 



under surface, which were left. lu so doing it ate a curved channel or 

 furrow from the edge of the leaf inwards and toward the base. Shortly 

 afterward it crawled to the under surface and stationed itself there in a 

 siniilai- way, now eating entirel}' through the leaf. I placed it with a 

 companion upon the upper surface of another leaf, and they at once trav- 

 elled to the under side and there remained resting side by side, head to 

 head or head to tail indifferently. I transferred them again just before the 

 second moult to the u[)per surface of a new leaf where they remained 

 throughout the third stage, eating while extended at full length on the 

 broad side of the leaf, though occasionally, in the early part of this stage, 

 they would feed at the edge, resting upon the same ; in the latter part of 

 it they woidd hardly have been able to do so from their weight. For when 

 travelling over the broad surfaces on which they move, they cover them with 

 zigzag lines of silk, and as Harris says "seem unable to crawl or hold on 

 without this precaution, for when placed on a fresh leaf the least motion 

 causes them to fall off." But this is true at almost any time, for the 

 amount of silk they spin is too slight to give them a strong attachment. 

 Edwards says (Can. ent., xiii : 13) "they are very active in their move- 

 ments, tar more so than any other of our [papilionid] larvae and can 

 travel with great rapidity"; yet they are rather slow eaters. The front 

 filaments are freely movable, and when travelling the caterpillars keep 

 them in constant motion up and down, generally alternating through 

 an angle of about 25°, in the downward movement just not reaching the 

 surface on which they are travelling. During their fourth stage I noticed 

 that when disturbed they had a curious habit, not before observed, of 

 tapping on the leaf repeatedly though not rapidly with the anterior pair 

 of legs, not simultaneously but one at a time. 



Their first use of the osmateria was at the very beginning of the second 

 stage, before eating anything, when under provocation I caused them to be 

 thrust out. When about to moult they could not be induced to use them ; 

 possibly they are powerless to do so. When full grown, I found it diffi- 

 cult to persuade them to display these organs : it was only through very 

 rough treatment that I could do so and in one instance I was unable by 

 the very roughest means to produce the slightest effect. W^hen they were 

 protruded the odor was hardly perceptible, and not altogether disagreeable, 

 thouofh difficult to describe. 



Although strictly gregarious in earliest life and semi-gregarious after- 

 ward, when full grown they distribute themselves anywhere over the 

 foliage, doing, according to Riley, great damage in Missouri to the orna- 

 mental climbing plants on wliich they live ; in one instance he "found the 

 vines literally denuded, for there was not a whole leaf upon them, those 

 that were not entirely eaten olF down to the stem being riddled with dif- 

 ferent sized holes" (Rep. ins. Mo., ii : llfi-118). There could be no 



157 



