76 VIEHMEYEK. 



Tiie possession of the organ used in serving the symbiotic relationship 

 appears very strange, in view of the profound histolytic and histogenetic 

 processes during the pupal stage. One might be induced to con- 

 sider the organ as rudimentary, in a manner similar to the abdominal 

 feet of some caterpillars, indications of which are still visible upon the 

 pupa. A comparison of pupa and caterpillar should then show the de- 

 velopment of the secretory organ in the former to be much less than in 

 the latter. The caterpillar producing this pupa is still unknown. A 

 short time ago I received from India caterpillars and pupse of Arhopali 

 amantes Hewits., which show similar relationship when compared from 

 this point of view. The pupse of this latter species are larger than that 

 under discussion and have also a myrmecophilous organ, though not 

 nearly as well developed. In a comparison between pupa and caterpillar 

 of A. amantes J with reference to their myrmecophilous organ it becomes 

 apparent that externally they are exactly alike. As the pupa from the 

 Philippines is much smaller than that from India, though having a much 

 larger and more strongly developed chitinous crater, it can not possibly 

 be assumed that this organ is rudimentarj', but it must be considered as 

 being completely functional. This would therefore indicate that the 

 living together of this pupa and the ants is no longer accidental, but has 

 become an obligatory relationship. • 



The myrmecophilous lycsenid caterpillars, as is well known, have, 

 besides the glands for producing honeydew, another organ which has a 

 relation to the symbiosis. On the eighth or penultimate abdominal 

 segment there are two tubes provided with a bristly rim which can be 

 drawn in or extruded like a pair of snail tentacles. In all- probability 

 these two epidermal tubes strengthen the symbiosis by attracting ants 

 through the secretion of a scent substance. By no means do the tubes 

 produce any kind of liquid secretion. It is therefore very worthy of note 

 that the tubes in the pupa from the Philippines are entirely rudimentary. 

 They appear only as a pair of slight depressions in the chitin. In con- 

 cluding that the epidermal tubes are scent organs for attracting ants, it 

 is at once apparent why the tubes and not the secretory organs have 

 become rudimentary in the pupal stage. The attracting of the ants and, 

 therewith, the functioning of the organs serving that purpose, naturally 

 become unnecessary in the ant nest, while the organs which serve in the 

 real sjoiibiosis retain their significance and utility. 



To sum up: We have here undoubtedly the peculiar spectacle of a 

 lepidopterous pupa acting as a food purveyor to ants, as it gives them, 

 from a chitinous crater, the secretion of two glands (in analogy with the 

 caterpillars) at least during the first part of the pupal stage. 



This singular occurrence induced me first of all again to make a 

 thorough investigation of all lycffinid pupse obtainable. But on none 

 could I discover myrmecophilous organs, and the symbiosis of the Phil- 



