THE DRAMA OF LIFE 53 



Lomechusa, as described by Wasmann, are very like ant 

 larvae. At any rate, the ants make little distinction 

 between the ant- larvae and those of their guests ; they treat 

 them both alike. Now it is the habit of the worker-ants 

 to dig up the ant-larvae and to clean them during the pupal 

 metamorphosis ; and they do this likewise for their guests' 

 larvae. But while it is a good procedure for the ant- 

 larvae, it is disastrous to the beetle- larvae ; the great 

 majority perish under the treatment and perhaps only 

 those which have been overlooked survive. Two naturalists 

 at least have referred to this as an unfortunate circum- 

 stance, as an illustration of the well-known fact that ' the 

 best-laid plans of mice and men gang aft agley ', but in 

 reality the apparent failure is an unconscious success ; 

 the result of the wheels- within- wheels complication is that 

 the friends of the family do not become too embarrass- 

 ingly numerous. 



Karl Jordan has made an interesting study of the glands 

 of Lomechusa and Atemeles and other related beetles which 

 live as guests in ants' nests. Numerous unicellular glands 

 on the sides of the abdomen produce the secretion that the 

 ants lick with evident gusto. But there are also numerous 

 offensive glands, common to other beetles of the same 

 sub-family Aleocharinae which are not myrmecophilous. 

 The secretion of these offensive glands has an odour like 

 that of amyl-acetate or methyl- heptenon, and it has, 

 like these substances, a stupefying effect on the ants. It 

 is used against stranger ants or against the hosts them- 

 selves when they are troublesome. The possession of the 

 offensive glands gives the beetles a certain standing, so to 

 speak, but it is on the possession of the palatable secretion 

 that the myrmecophilous partnership depends. 



