WHEELER— ANT LARV^. 331 



likens to the conscious artificial selection employed by man in 

 perfecting the numerous, often bizarre varieties among his domes- 

 ticated animals and plants. Escherich (1898, 1902, 191 1), Schim- 

 mer (1909, 1910) and I (1910) have never accepted this view, and 

 J am still unable to see that Wasmann has successfully disposed of 

 our arguments. The whole matter comes down to the answers to 

 two questions : Do ants and termites possess special symphilic in- 

 stincts ? and : Is the assumption of amical selection necessary to ac- 

 count for the facts? In my opinion both questions are to be an- 

 swered in the negative. 



It is unnecessary to consider all the various symphiles which 

 Wasmann has so long and so carefully studied. A brief account ot 

 Lomechiisa strumosa, his chief battle-horse and according to his own 

 statement one of the most typical of symphiles, will suffice. This is 

 admittedly a predatory parasite in the colonies of Formica san- 

 guiiiea. Its larvae devour the ant larvse and the adult beetles are 

 fed and licked by the ants. The fat tissue of the larva probably 

 supplies the ants with an agreeable exudate and the adults certainly 

 furnish an agreeable secretion from their abdominal trichome glands. 

 When the larvse, which are evidently treated as if they were ant 

 larvse, mature, they are buried in the soil, just as the ant-larvse are 

 buried, in order that they may pupate. The pupse are also un- 

 earthed like the ant pupae, after they have spun their cocoons, but 

 this treatment is fatal to the parasites and only those that have 

 been forgotten and left in the soil are able to develop into beetles. 

 Often the greater part of the ant brood is destroyed by the Lome- 

 chusa larvse, but in some colonies, by a process which Wasmann 

 has never adequately explained, many of the larvae develop into 

 pseudogynes, or forms intermediate between workers and females. 

 These pathological individuals are unable to perform the functions 

 of either of the castes which they imperfectly represent. This is in 

 its essential outlines the history of Lomechiisa. Now Wasmann be- 

 lieves that Formica sangiiinca has acquired during its phylogeny a 

 special symphilic instinct which impels it to foster Lomechusa to 

 the detriment of the colonies and therefore to the detriment of the 

 species, and regards the case as furnishing a splendid argument 

 against natural selection and an incontestible proof of the existence 



