2 ARKIV rÖR ZOOLOGI. BAND 10. N:0 G. 



Wales II, 1872, p. 27). Afterwards it does not seem to 

 have been rediscovered; at least nothing in låter literature 

 dealing with tbe species can be found. 



The myrmecophilous group of Australian Ptinidce af förd a 

 special interest. In tbeir organisation they show very pecu- 

 liar adaptations to their life among tbe ants. Indeed, some 

 of them show sucb a striking similarity, in regard to tbe 

 antennse, with tbe true Paussidce, tbat some autbors have felt 

 convinced of their genetic relationship with tbe latter group. 

 Thus, even sucb a good coleopterologist as Lea, to wbom 

 we are so greatly indebted for bis ardous studies of tbe 

 Australian insects, and for bis many valuable descriptions 

 and good illustrations of bis new genus Paussoptinus, writes 

 as follows: »Tbis genus is proposed to receive a small beetle 

 clearly intermediate between tbe Paussidce and Ptinidce, se- 

 veral otber genera have been noted as connecting links be- 

 tween tbe two families, but there is none so absolutely con- 

 vincing as tbis» (Proc. R. Soc. Victoria XVII. 2. 1905, 

 p. 381). 



The above mentioned similarity is clearly due to tbeir 

 common myrmecophilous habits and illustrates beautifully tbe 

 biological conception : convergence. The systematic position 

 of tbe Paussidce as being closely allied to tbe Carahidce among 

 tbe Adephaga seems to be definitely settled. 



It is of great interest to follow tbe development of tbe 

 antenn^e among tbe myrmecophilous Ptinidce. The most un- 

 modified seems to be tbe genus Diplocotes, having tbe full 

 number of joints with only tbe tenth joint a little specialized. 

 To tbis genus also a couple of species {D. decemarticulatus Lea 

 and D. strigicoUis Lea) with only ten joints have been re- 

 ferred. I think there are good reasons to keep these two 

 forms with reduced numbers of joints separate. I have 

 preferred to place them in a new genus which I call De- 

 cemplocotes. Then comes tbe genus Polyplocotes with only 

 nine joints, and with tbe eigbth joint specialized (laterall3'' 

 compressed). Four species were hitherto known, but tbe 

 present material contains a new one, bringing tbe number 

 up to five. 



In tbe very remarkable genus Paussoptinus described by 

 Lea in a species called P. laticornis tbe antennse show a 

 specialization on a totally different and very characteristic 



