322 THE MYRMECOPHILOUS COLEOPTERA 



a period of several days, when tliey leave the Myrmica nest, as they remain 

 hidden in and near the new Formica nest. When they go from Formica to 

 Myrmica the period is much longer, as they are not found with the latter before 

 the end of August, or beginning of September, though they have long before 

 disappeared from the Formica nests. Having been bred in the latter nests, 

 the nest aura is no doubt more pronounced in the beetles of the summer 

 migration. They are also said to cause pseudogynes to be produced in the nests 

 of their hosts. I have found pseudogynes in plenty in nests of Formica rufa, 

 and rufo-pratensis at Nethy Bridge in Scotland. It is therefore certain that 

 if the theory is correct we possess another species of Atemeles, most probably 

 A. pubicoUis, a continental species, whose hosts these ants are. 



(2) In the hostile persecuted lodgers Ave find that, though attacked, they 

 are able to protect themselves, even when introduced from one species of ants' 

 nest into another. They live as beasts of prey, and murderers in the nests 

 of the ants and their j'oung. Their size prevents the ants from tolerating 

 them. Such are the Myrmedonias, all of which are ant-eaters, Quedius brevis, 

 Xantholinus atratus, &c. Lamprinus saginatus is another example, and is 

 found with various ants. It hides in the nest, and steals and devours the 

 ants' eggs. Myrmedonia funesta, which is found with the tree-ant Lasius 

 Juliginosus is a good example of mimicry, as it is very like its host, being 

 jet-black in colour. Wasmann has expressed his opinion that this mimicry 

 is to deceive the ants. Here I am unable entirely to agree with him. I 

 consider it is more to protect the beetle from outside enemies, and what I 

 think goes far to prove this is that as the beetle when introduced into my nest 

 of Formica rufa was able, when attacked, to defend itself against so fierce an 

 ant, it would not therefore require protection by mimicry with its own host. 

 Wasmann truly says that when disturbed it curls up and looks like a bit of 

 earth, but that is surely its second line of defence. The insect is found in 

 the runs and outside the true nest, where its resemblance to the ants would 

 be of most use in the case of outside enemies. On the other hand, Thiasophila 

 inqibilina, a much smaller beetle, which occurs with the same ant, and is of a 

 rather bright red-brown when alive is nearly always, when found, in the deeper 

 part of the nest. I have seen it make use of the same defence as Myrmedonia 

 tphen attacked by an ant. The defence of these beetles is as follows : when 

 the beetle meets an ant it stands still and raises the abdomen over the body, 

 and if the ant tries to attack it, it pokes the end of the body into the ant's 

 face. The ant starts back, and the beetle resumes its career. When I have 

 forced an ant to take hold of a beetle, it very soon let go and often ran round 

 and round in a circle as if mad, and sometimes one antenna would remain 

 bent in one nosition for some time, as if stiff. These beetles possess a strong 

 pungent smeil, which is most noticeable when handled, and it is this vapour 

 they give off which, I consider, protects them from the ants. I have dis- 

 sected several species of Myrmedonia {and also Lomechusa, which I discovered 

 gave off a similar smell when seized) under the microscope, and have found 

 the glands which secrete this vapour. For some years past I have been 

 trying to find out its chemical formula, but the difficulty in obtaining sufficient 

 of the substance is very great. The Myrmedonias and Drusilla canalicidata 



