SOME EXPERIMENTS WITH MYRMECOPHILOUS COLEOPTERA. 351 



with the ants. On May 14th a specimen was walking about, and on 

 May 2Gth another was seen in one of the galleries. It will be observed 

 that this specimen had been a month in my nest, since it was 

 introduced. 



Miirmedonia fnnesta, Grav. — The experiments with this beetle are 

 still more remarkable than the last, because though the specimens of 

 M. hnmcralia already referred to, came from the nest of Lastiis fitlifjinosus, 

 still the species does occur with F. ntfa, whereas M. fitncsta is only found 

 with Lasiiis fidiiihiosus. On April 12th I brought up some specimens of 

 this beetle from a nest of Lasiiis fiditjinosiis at Oxshott. I introduced 

 several examples into my nest. An ant seized one fiinesta by the 

 antennffi and began to drag it along, when suddenly it let go and crawled 

 into a corner as if dazed, rubbing its head on the ground for some 

 time. The other specimens of fnnesta when attacked used the same 

 defence as Dinanla with equal success, and hid themselves in the nest. 

 On April 13th I repeated the experiment. I introduced another 

 fioiesta, an ant seized and closed with the beetle, and another ant 

 joined in, also taking hold of it. The beetle was held tightly by both 

 ants, when they suddenly let go and wandered about in the same dazed 

 way as in the former experiment. One of the ants had a stift" antenna 

 which remained so for some time. The beetle walked quietly away 

 unhurt. The " Myrmedonia " smell was very noticeable at the time. 

 On April 14th a, fnnesta was running about in the nest, and when it 

 met an ant it used the usual defence. On May 8th, having caught some 

 more examples of M. fnnesta, I put several ants from my nesfc into a small 

 box with the beetles and left them together all day. The beetles were 

 unhurt. I think this clearly demonstrates that these beetles possess a 

 special means of protection against even so fierce an ant as F. ru/a. I 

 think that this means of defence takes the form of an acid which the 

 beetle emits as a vapour when molested, that this acid is not formic 

 acid, and that it is very offensive to the ants. I placed a number of 

 Myriiiedunia in a tube with filter paper soaked with distilled water, and 

 kept shaking them up. On removing the beetles the tube smelt 

 strongly of the " Myrmedonia " odour, and I am endeavouring to have 

 it analysed, though the difficulty must be great with so small a 

 quantity. 



Mynnedonia Iwjens, Grav., and M. laticoUis, Mark. — I tried similar 

 experiments with these as with the last two species. The defence is 

 the same, though not so marked, as when an ant is forced to seize 

 them, it does not drop them as quickly, dragging them about more. 



Astilbiis canalictdatKs, F. — Having brought up from Portland a 

 number of this species from the nests of Lasius jianis and L. niijer, 

 on April 23rd, I introduced several into my rnfa nest, they ran about 

 and entered the nest, appearing to avoid the ants by their quickness, 

 hiding under twigs, &c. I placed two of my ants in a small box with 

 several Astilhm, their mode of defence proving to be the same as in 

 Dinarda. Left all day and no Astilhus injured. When, however, an 

 ant is forced to seize an Astilhus it does not let go, as with Mijrme- 

 donia, but drags the beetle into the nest. On June BOth I saw an 

 Astilhus come out of the nest and run quickly about, hiding itself 

 among the pine needles. 



Myrmedonia Ihnhata, Payk. — This beetle exhibits an exactly parallel 

 case to Astilhus. It will be remembered they are not so truly myrme- 



