MYRMECOPHILY OF CATERPILLARS. 71 



comyntas GocTt. He disiDoses of the question of the presence of evaginat- 

 ing tubeSj or "caruncles" as he calls them in parentheses, by, "First noticed 

 in the third stage." Indeed, of the caterpillars of the genus Rusikus 

 Hiibn., he then says, "A transverse slit in the middle of the dorsum of 

 the seventh abdominal segment appears in the third stage, but appar- 

 ently the caruncles of the eighth segment do not appear until the fourth 

 stage." 



Prom the extraordinarj- similarity of the caterpillars and the almost 

 perfect similarity of structure of the myrmecophilous organs, I do not 

 believe that such a striking difference could exist, but rather think that 

 an error lies therein. Another question here arises, and that is as to 

 whether the organs, as Edwards questioned, are really functional in the 

 earlier stages of the caterpillar's existence. 



I have recently noticed that Gillmer " also affirms that in caterpillars 

 of Lyccena argyrognomon Bergstr., the pore is developed first in the second 

 stage and the tubes first in the third stage. It is then certain that the 

 earlier statements concerning this are not exact. 



Finally, the first stages of the caterpillar of C. cncjiis must be con- 

 sidered from another standpoint. Thomann ' has made certain careful 

 studies upon the integument of the caterpillars of myrmecophilous Lycas- 

 nidffi. He found that the skin is covered with "star-shaped warts so 

 exceedingly small that they can not be seen by the naked eye and that 

 from their centers grows a single minute bristle with, usually, a tuft of 

 fine hairs at its tip." He sees in these growths possible organs of touch, 

 which may serve to notify the caterpillars of the return of the ants. 



This view appears to be reasonable, especially as in the region of the 

 myrmecoj^hilous organs there is usually to be found an accumulation of 

 these tufted hairs. In the young caterpillars of 0. cnejus there are three 

 interesting facts to be noted: That the tufted hairs appear after the 

 first moult simultaneously with the opening of the pore; in this stage 

 they remain proportionately sparse and appear especially aroiind the pore, 

 but not in masses ; after the second moult, they show in the same numbers 

 and with the same arrangement as in the fully developed larvae. 



The ant which visits this caterpillar is Polyrhachis dives Smith (det. 

 Porel.) Green's supposition that the pupation of the caterpillar takes 

 place in the ant's nest appears to be without foundation. The appearance 

 of caterpillars of Lycffinidte in ants' nests seems to me, at least for the 

 European species, to be more or less accidental and then only if the ants' 

 nests are upon the ground in the immediate vicinity of the food plant 

 of the caterpillar. 



' Ein literarischer Beitrag zur Grosschmetterliiigsfauna von Liibeek. Arch. d. 

 Ver. d. 'Naturgesch. in MecJc. (1907), 6L 

 ' Sehmetterlinge und Ameisen. (1901). 



