DINARDA PYGM^A, WASMANN. 217 



Dinarda pygmaea, Wasmann (Deutsch. Ent. Zeit., 1894, p. 277), a 

 species of Myrmecophilous Coleoptera new to Britain. 



By Horace St. J. K. Donisthorpe, F.Z.S., F.E.S. 

 Having heard that it has been asserted that Dinarda hagensi 

 is the same species as D. dentata, or at least, as the beetle taken by 

 Mr, Keys in Cornwall, two or three years back, and Avhich was named 

 D. dentata for him, and the ant with which it was taken Formica ftisca, 

 I compared Dinarda hagensi with my "Woking specimens of Dinarda 

 dentata, and of course, found them distinct species, as I had done 

 before with my Wellington College D. dentata. It then occurred to 

 me that I had got a specimen of Mr. Keys' insect which he had kindly 

 given me, and which I had put into one of my "ants'-nest drawers." 

 On comparing this with D. hagensi and D. dentata, I found it was quite 

 distinct from both of them, so I at once sent it to Father Wasmann, 

 and told him it had been taken with Formica fnsca; also that Atemeles 

 paradoxus had been taken in the same nests both by Mr. Keys and 

 myself. He returned it to me as Dinarda pygmaea, Wasmann. He 

 pointed out, however, that Atemeles paradoxus does not occur with 

 Formica fusca (and neither, of course, does Dinarda dentata), but both 

 it and Dinarda pygmaea are found with Formica rufiharbis var. fusco- 

 rufibarbis. For. Mr. Keys, on hearing from me, went to get some of 

 the ants, and he sent me specimens from three of the nests, which I 

 sent on to Father Wasmann, and they are all Formica rujibarbis 

 var. fusco-rufibarbis. For. This is exactly what was to be expected, as 

 true ants'-nest beetles are exceedingly constant in keeping to their own 

 hosts, a point 'which one begins to appreciate after a good many years 

 collecting in ants' nests, and which I should like to impress upon 

 coleopterists. When one does get a species away from its own hosts, 

 it is only by chance, and singly. The following is a table showing 

 the relationship of the Dinarda family and their hosts : — 

 Ancestral type of DiNAEDiNn (Unknown). 



i 

 Dinarda, Grav. 



iEthiopian. Palsearctio. 



1. D. clavigera, Fvl. 2. D. nigrata, Eosh. 3. D. dentata (group). 



(Abysinnia, Host: unknown). (Mediterranean, Host : (North and Central Europe, 



Apliaenogastcr te^lacea- Host: Formica). 

 pilosa, Lac). I 



I I I 



a. D. mdrkeli, Ksw. b. D. hagensi, Wasm. c. D. dentata, Grv. 

 (Host: F. rufa, L.). (Host: J*", exsecta, Nyl.). (Host: F. sanguinea, Ltr.). 



d. D. dentata var. minor, 

 Wasm. 



Host : 



F. rufibarbis var. -i e. D. pygmaea var. denta- 

 fusco-rufibarbis , For. toides, Wasm. 



f. D. pygmaea, Wasm. 



I 



g. D. pygmaea var. tiigri- 



toides, Wasm. 

 Septembee 15th, 1906. (Host: F. fusca, L.). 



