12C HORN KXPKDITION — NAIiRATTVK. 



Amongst plants certain gcnora, wei'o oqually doniinant. On the Hats and along 

 tho valleys amongst the ranges Cassias, Acacias (especially A. aiicura), Eremophilas 

 a7id Eucalypts formed the mass of the \egetation and on the rocks the Pine tree, 

 whilst the Porcupine grass (Tiiodia sp.) dominated alike both \alleys and the 

 rockiest hill sides. 



Under a l)lock of quartzite in the lied of tlio gorge I came across a small nest 

 of honey ants of wiiich numerous specimens have since been found l)y Mr. Cowle. 

 Tt was a very different form of nest from tliat of Camponotus iitjlalits but tliis was 

 probal)ly only a young colony. Purrows liranched oil' in all dir(K-tions luit did not 

 go far down. The ants weie of a rich golden colour and the insects were nothing 

 like so swollen out as in those of tlie first-named species. Though their abdomens 

 were inflated so that the terga and sterna were all separated from one another still 

 they were capal)le of a certain amount of mo\ement. 



In the Mulga scruli at the liase of the range there were two forms of ant 

 nests wliich were frequently met with evei-y where amongst the scrub fi'om Ayers 

 Pock in the south to the Burt Plains in th(^ north. One has the form of a mound 

 upwards of two feet in diameter and about six inches high, with a large, crater- 

 like depression at the top. Around the sides of the mouufl the ants arrange a 

 tliick deposit of dead Mulga leaves all placed i-adially in a perfectly regular 

 manner. The other mound is the same size but instead of the crater depression it 

 has a slit from three to si.K inches in length and half an inch to an inch in width 

 and is always covered over with various kinds of dried grass seeds ; the nest is 

 inhabited by one of the numerous species of Camponotus (C. denticiilatits). Both 

 of them have passages leading away in various directions, but though I spent some 

 time here and elsewhere in trying to follow them up the hard, stony ground 

 prevented this being done satisfactorily and the large lilack ants inhabiting them, 

 which were from half to three-quarters of an inch in length, enforced a certain 

 amount of carefulness as they naturally objected to having their homes broken up. 



It is difficult to see what is the use of the Mulga leaves and the grass seeds 

 as I coukl detect nothing such as a fungoid growth amongst them, though this 

 might l)e present under different climatic conditions, or anything which could be 

 of service to the ants, and whilst the Mulga leaves might serve to drain oH' water 

 during the rain season the grass seeds would rather have the opposite effect. 



After spending the day collecting in the gorge and along the flats by the 

 creek and on the hill side we went back to camp and found that the black l)oy 

 had brought in five rock wallal)ies {Pc/>-oga/c /a/cra/is). This is at once dis- 



