324 



THE MYRMECOPHILOUS COLEOPTERA 



these lodgers inhabit the nests entirely for their own advantage, they are 

 probably of some use to their hosts also ; indeed, one Avould imagine if 

 this were not so, the ants would have acquired a means of ejecting them. 

 Our four species, or races, of Dinarda each live with a distinct species of 

 ant. They are probably all descended from a common ancestor of Dinarda 

 dentata, which is the oldest developed species. The nests and habits of their 

 hosts are very different, and this has no doubt played a considerable part 

 in the evolution of the species. Dinarda mcirkeli is found with Formica rvfa, 

 which builds the well-known hillocks of pine-needles. D. dentata occurs with 

 F. sangiiinea, the slave-maker, Avhich makes its nest chiefly in banks, Avith 

 very little nest materials over the nest. D. Jiagensi inhabits the nest of 

 J^. exseda, whose small nests, about the size of a football, are built of grass 

 and ling. This rare ant was only supposed to occur at, and in the neighbour- 

 hood of Bournemouth. Mr. Hamm, however, has found it in Devonshire, 

 Mr. Blatch recorded it from Bewdley in the Midlands, and I have discovered 

 it in the Highlands of Scotland, and in the Isle of Wight. D. pygmaa lives 

 with F. fusca v. fusco-rtifilarbis, which chiefly nests under stones. The 

 following extract from a table by Wasmann will show the relationships of 

 the species in connection with their hosts : 



Antestral Type of Dinardinii (unkno^Mi). 

 Dinarda, Grav. 



Aethiopian 



Palsearctic 



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



(Abyssinia, Host : un- (Mediterranean, Host : (Xorth and Central 



known). Aphcenogaster testaceo- Europe, Host : Formica), 



pilosa). I 



D. markeli, Ksw. 

 (Host : F. rvfa, L.). 



D. hagensi, Wasm. c. D. dentata, Gr. (Host : 



(Host: F. exsecia,'i^jl.) F. sanguinea,'Ltv.). 



Host : F. rufiharhis 

 var Jusco-rxifiharhis, 

 Por. 



{d) D. dentata v. minor, 

 Wasm. 



I ' 



(e) D. pi/gmcea v. denta- 



toides, Wasm. 



I 

 (/) D. fygmcea, Wasm. 

 {g) D. pygmeea v. nigri- 



luides, Wasm. (Host : 



i''; fiii'fa, L.) 



