404 Mr. H. St. J. Donisthorpe on the Origin 



will discuss this more fully when we have dealt with 

 Astilhns. I pointed out (" Some Experiments with Myrme- 

 cophilous Coleoptera," Ent. Rec, 1901, p. 351) that 

 " This beetle exhibits an exactly parallel case to Astilbus. 

 It will be remembered they are not so truly myrme- 

 cophilous (not invariably being found with ants) as are 

 the other species of Myrmedonia." 



Astilbus canaliculatus, F. 



This very widely distributed species is found " In runs of 

 Formica fiava and other ants, also under stones in hay- 

 stack refuse, decaying seaweed, moss, etc." (Fowler, /. c. 

 p. 59). It also feeds on ants. Bold in 1848 wrote — " Often 

 tenanting the nests of ants, and preying on the inmates " 

 (Col. North, and Durham, p. 134). Messrs. Lucante and 

 Bleuse recorded that it captured and killed ants (E. M. M., 

 1876, xiii, p. 65). I took a specimen at Chiddingfold 

 running with a dead Myrmica in its mouth, and Walker 

 took it under similar circumstances at Tubney. I have 

 kept specimens alive for months in small plaster nests 

 by giving them ants out of my different observation 

 nests, which they always devoured. It has been recorded 

 with Lasius flavus at Mickleham (F. Smith) ; with 

 Lasius fuliginosus at Chobham (Saunders) ; Wellington 

 College (Joy) ; Guestling (Collett) ; with Formica rufa, 

 Chobham (Saunders) ; Scotland (White) ; with Myrmica 

 laevinodis, Guestling (Collett) ; in ants' nests. Isle of Man 

 (Bailey) ; Lundy Island (Joy). 



I have taken it with Lasius fiavus at Sevenoaks, 

 Hastings, Eastbourne, Portland, etc. ; with Formica 

 sanguinca at Wey bridge ; with F. fusca and L. niger at 

 Portland ; and with Lcptothorax acevorum at Fairlight, etc., 

 etc. In experimenting with the defence of this beetle 

 against ants (/. c), I found that if an ant was forced to 

 seize an Astilbus it does not let go, as with Myrmedonia. 

 The Astilbus exhibits the same form of defence {i. c. 

 thrusting the tail in the ant's face and giving off the 

 Myrmedonia smell), but it is evidently not so perfectly 

 developed. We can imagine, that as it developed the 

 glands which secrete the smell given off, it would be able 

 to inhabit the nests with greater impunity and gradually to 

 become a more regular guest. No doubt some such steps 

 as these have taken place with the other Myrmedonias. 



