THE MYE.MECOPHILOUS COLEOPTERA 323 



kill and devour ants. Mons. L. Mesmin mentions that a specimen of Jlyrmedonia 

 collaris he put into a bottle with two ants, immediate^ seized one of them and 

 killed it. I have seen Myrmedonia cognafa attack and kill ants in captivity, 

 biting them behind the head, and have kept most of our si^ecies alive for a 

 long time by giving them ants to eat. In a wood, in Worcestershire, where 

 Myrmedonia hmneralis was abundant, I saw many ants killed by the beetles. 

 Near one large nest of Formica rufa a cart-track went through the wood, and 

 in this track the Myrmedonia occurred in every crack and under every dead 

 leaf, and also many of its larvae. Every here and there little heaps of dead 

 ants were to be found, and these kept being added to by the IMyrmedonias 

 Avith specimens they had slain. The beetles could be seen hiding and pouncing 

 on a solitary ant. Thousands of the ants must have been killed in this waj'. 

 Messrs. Leucante and Bleuse record Drusilla attacking and killing ants. 

 Commander Walker found it carrying an ant, and I have taken it at Chidding- 

 fold with a dead Myrmica in its mouth. The copulation in Myrmedonia is 

 the same as that of Lomechusa. 



(3) The indifferently treated lodgers are mostly scavengers in the nests 

 Some are very small, such as Ptenidium and Ptilium, and the ants appear to 

 pay no attention to them whatever, it is just as if they were invisible. The 

 two species of Monotoma have a very wooden appearance, and when motionless 

 much resemble bits of wood, or other debris on the ant-hill. I have seen 

 specimens walking on the top of my nest amongst a lot of ants who never 

 took the slightest notice of them. I have even seen them walk over the ants. 

 Oxypoda and some other of the smaller " staphs " are protected on account 

 of the quickness of their movements. The Histeridce are protected by their 

 very hard bodies, the ants not having strong enough jaws to bite them. 

 George Lewis noted the same with the " Formicarius Histers " in Spain and 

 Tangiers, which he generally found feeding on the larvae of the ants. Their 

 hosts seemed indifferent to, or unconscious of, their presence, and appeared 

 to know that they were physically incapable of freeing their nests of these 

 hard beetles, their jaws not being strong enough to hurt them. Two of our 

 species, however, Hetcerius ferriiginetis and Myrmetes piceus, are approaching 

 the true guests, as they are often licked by the ants. I have noticed this 

 myself with the latter. During copulation, which I have noted in May, the 

 male of this beetle, sits far back on the dorsum of the female. I introduced 

 specimens into a nest of F. fusco-rufiharhis, and had given these ants pupa^ 

 of F. rufa to eat. The Myrmetes bored into the pupae and devoured tli! 

 whole contents. 



The genus Dinarda is generally classed in this group. Although the 

 ants often try to attack them, and they protect themselves in the same way 

 as I have shown the Myrmedonias do, they do not attack or kill the ants. 

 They sometimes steal and devour the ants' eggs. I have seen a Dinarda creep 

 underneath two ants feeding at some sugar and pilfer some of it. They also 

 feed on the acari, which are a great pest in some nests. I kept a single 

 Dinarda alive for months in a small plaster nest with a small colony oi 

 Formica exsecta. The ants were covered with the young of acari, and the 

 Dinarda practically cleared the nest of them. Tliis shows that though 



