Dec, '04] ENTOMOLOGICAL NEWS. 34I 



causal relation, which Father Wasmann had established for 

 F. sanguinea and L. strui7iosa should exist between F. rjibi- 

 ciinda and X cava. 



But in spite of continued investigations I was unable to 

 substantiate this proposition any further, and in all probability 

 there is no hope at present to secure new material in this 

 region . 



In the spring of 1902 the only nest of F. rubicunda which 

 contained pseudogynes and was located in the district of 

 Xenodusa cava, was found totally destro3'ed by heavy rains. 

 In the numerous other nests of F. riibiciaida there were no 

 traces of either pseudogynes or larvae of Xetiodusa cava. 



It is hoped, however, that this brief notice will suffice to 

 induce such as are interested in the biology of ants to give their 

 attention to the remarkable relation mentioned above, as well 

 as to search for further facts which would confirm the one 

 observed in this region. 



I close this paper by calling the attention of the reader to 

 the interesting question how this strange relation between the 

 existence and development of pseudogynes and the rearing of 

 the larvae of Xenodiisa cava ought to be explained. Wasmann 

 is of the opinion that the repeated rearing of the beetle causes 

 a gradual change in the brooding instincts of the ants, so that 

 the pseudogynes are but a developmental stage of such larvae, 

 as were originally destined to become females, but in course 

 of their later development were transformed into workers. 

 Besides, an interesting psychic problem is suggested by the 

 fact that it is the fault of the ants themselves that these encum- 

 brances on their commonwealth come into existence and mul- 

 tiply with such rapidity. 



Of the numerous publications of E. Wasmann, S.J., on this 

 subject we mention especially the following : 



1. Die ergatogynen Formen bei den Ameisen und ihre 

 Erklaerung. Biologisches Centralbl. XV., 1895, pp. 606-646. 



2. Kritisches Verzeichnis der myrmekophilen und termito- 

 philen Arthropoden. Mit Angabe der Lebensweise und Besch- 

 reibung neur Arten. Berlin, 1894. 



3. Neue Bestaetigungen der Lomechusa-Pseudogynentheorie, 

 Verhandlungen der deutschen Zoologischen Gesellschaft, 1902, 

 pp. 98-108. 



EXPLANATION OF PLATE XX. 

 Fig. I. — Xenodusa cava 'Lee. (original). 



Fig. 2. — Formica sanguinea subsp. rubicunda, Em. a = female ; b = 

 pseudogyne ; c = normal worker (original). 



Fig. 3. — Thorax of a normal worker of F. rubicunda (original). 

 Fig. 4. — Thorax of a pseudogyne oi F. rubicunda (original). 



