144 LIFE STORIES OF AUSTRALIAN INSECTS. 



but tlie one always had nothing but mulga leaves, 

 and the other nothing but grass seeds." 



Professor Spencer gives an interesting account 

 of the nest and habits of the porcupine-grass ant 

 (Hypoclinea flavipcs) found in the desert area of 

 Central Australia. 



''Various explorers have already noted the pres- 

 ence of curious little galleries which run along the 

 surface of the ground, often for long distances, from 

 one tussock of porcupine grass to another. In some 

 parts, and especially on hard, sandy soil where the 

 tussocks of grass are not too close together, these 

 galleries, as they are called, though tunnels would 

 be a better name, form a regular network. Each 

 is from one quarter to half an inch in width, and, 

 in section, is roughly semicircular in shape. They 

 are made of grains of sand fastened together with 

 the resinous material obtained by the ants from the 

 gelatinous leaf sheaths of the Triodia (porcupine 

 grass), and they form runs which lead from one 

 tussock to another, along which the ants can travel 

 sheltered from the light, and more especially, per- 

 haps, from the heat of the sun. In many cases 

 they lead for long distances up the trunks of gum 

 trees. 



In addition to the galleries running along the 

 ground some of the tussocks of porcupine grass 

 have their long spiny leaves more or less wholly 

 enclosed in little cylinders of sand, formed in the 

 same way, to such an extent that the whole tussock 

 looks like a network of sand tubes. In other cases 

 there w^ere only small cylindrical cases of sand here 



