318 



THE ZOOLOGIST. 



it has six legs, it does not use them, but imitates the movements of the 

 ant-grubs. The ants prefer the beetle larvae to their own, and even 

 place them on their egg-masses (as the Lomechusa larvas devour the 

 ants' brood), as well as feed them by mouth. The too great care taken 

 by the ant prevents the over-increase of the Lomechusa, as, after its 

 larva has pupated, the ants dig it up to see how it is getting on, and 

 by this means many are destroyed, as the delicate pupa is killed, or 

 dries up. The most interesting problem, however, concerning Lome- 

 chusa is the production of pseudogynes, or false females, among the 

 worker-ants, in nests where the voracious beetle has been established 

 for some time, and these nests which possess pseudogynes are the 

 centres from which Lomechusa spreads to other colonies. Pseudogynes 

 are produced in nests where the ants have lost their natural instincts 

 as nurses to their own brood, and give all their attention to the Lome- 

 chusa. In nests where pseudogynes are found collectors may be sure 

 of finding Lomechusa ; they are workers with a high mesonotum some- 

 what as in the queens. The following sketch shows the three forms : — 



Pr., 



Pr, = pronotum. 



Pr..- 



2 3 



1 = queen. 2 = pseudogyne. 3 = worker. 

 Ms. = mesonotum. Set. = scutellum. Pst. = post-scutellum. 

 Ep. = epinotum. 



A similar case occurs with the American ant, Formica sanguinea 

 snbsp. rubicunda, Em., and its guest, Xenodusa cava, Lee, a beetle 

 allied to Lomechusa. Pseudogynes have also been observed with the 

 hill-ant, Formica rufa, caused by the continental Atemeles pubicollis, 

 Bris. — Horace Donisthorpe (58, Kensington Mansions, South Ken- 

 sington). 



