1892.] Ql 



stones, and on these subsist several species of root-feeding Aphides 

 and Coccids. Two species of the former, a white and a scarlet, and two 

 of the latter {DactyJopius pocd, Maskell), and a new species of Sipersia, 

 occur in the nests of the Tetramoria. There are also numbers of 

 slate-coloured mites, and a minute white form of JPlatym^thrus in- 

 habiting their nests ; along with these I have discovered a new genus 

 of formicarious beetles {DlartliroceraformiccBpthila, Broun), lately ex- 

 amined and named for me by Capt. Broun. The habits and economy 

 of these "hosts" and parasites do not differ materially from other allied 

 species recorded by Lubbock and others as inhabiting the nests of 

 British ants. Their occurrence, however, illustrates the general rule 

 that parasites and serviceable species are more or less present in all 

 ants' nests in all parts of the world, at least, so far as their economy 

 has been investigated. I am not aware that the occurrence in certain 

 localities of several species of root-feeding Aphides and Coccids has 

 been observed by entomologists as forming the basis of ants' nests, 

 yet, according to my researches, such is the case with our Tetra- 

 moria. After the annual flight, which generally occurs in Pebruary 

 and March, according to the conditions of the atmosphere, I have 

 frequently observed isolated individuals of both sexes and both species 

 roaming about among the boulders lying among the stunted and 

 mixed vegetation. By the middle of May, when the colder weather 

 sets in for the winter, or rainy season, they disappear, and are very 

 rarely seen above ground ; while endeavouring to ascertain what 

 became of the ants when they disappeared, we discovered a clue to 

 the origin of their nests. In order to test and settle the question 

 perfectly, we have been in the habit of turning over hundreds of 

 boulders annually, and carefully noting the origin and development 

 of their nests. From the middle of April and onwards through the 

 winter we have observed many instances of only a few ants of both 

 sexes being associated together : in numbers we have noted from two 

 up to eight and ten together, and from these we have watched their 

 increase and development into various and good-sized communities 

 in a single season ; searching for these founders of new nests requires 

 to be done with great care, as very little causes their occupants to 

 desert the site, which is disappointing. But this is due chiefly to the 

 Aphides and Coccids feeding on the roots beneath changing quarters, 

 caused by the admission of air and light while turning over the 

 boulders. 



I have mentioned the presence of Aphides and Coccids feeding 

 on the roots beneath the boulders, as forming an economic basis for 



