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NATURAL LOCALITIES OF BRITISH COLEOPTERA. 79 
ligniperda; these burrows usually contain a goodly number of 
parasites, if they can be strictly so called, attracted apparently by 
the scent and high flavour of the Cossus larva; among them may 
be mentioned Huryusa laticollis, Cryptarcha strigata and umperialis, 
Epurea decem-guttata, and two or three species of Homalota. 
Some beetles, as has before been said, are parasitic upon 
others, as Colydiwm elongatum and Oxylemus cylindricus on 
Platypus cylindrus, and Teretrius picipes on Ptilinus pectinicornis ; 
this sort of parasitism probably occurs in more cases than we 
know of, and is worthy of more attention from coleopterists than 
it generally receives. 
Of all forms of parasitic beetles, however, those that inhabit 
ants’ nests are the most interesting; the true ant’s-nest beetles 
all belong to the Clavicorn group, and are very likely the 
scavengers of the nest; some of them probably give forth odours 
or secretions that please the ants, ike the Aphides; it has been 
suggested that some species, like Batrisus venustus, are kept by 
the ants as pets, but this seems hardly likely; whatever their use 
may be the ants take the greatest care of them, and, if the nest 
is disturbed, may often be seen carrying beetles much larger than 
themselves into places of security; they do not, however, 
apparently always act with the gratitude one might expect from 
them, as a Myrmedonia has been known to devour ants with 
which it has been shut up; it is, however, quite possible that the 
beetle was put m with strangers, or that its altered circumstances 
induced it to behave in so barbarous a fashion. 
The ant’s-nest beetles were first really brought under the 
notice of British collectors by the excellent paper of Mr. E. W. 
Janson in the ‘ Hntomologist’s Annual’ for 1857, and full direc- 
tions are there given for working them. 
Around the larger ants’ nests (such as those of Formica rufa) 
stones and logs of wood should be carefully laid, and from time 
to time these should be taken off and closely examined; many 
good species will be found attached to them. A great number of 
ants make their nests under stones, and raise no heap, or none 
worth mentioning: when these stones are lifted they should be 
put in a cloth or ina bag and left, while the collector at once 
without delay examines the runs, for if he stops to examine the 
stone first, the ants will have carried all the beetles out of sight ; 
if this plan be adopted with the flints in the chalky districts near 
