J"^^'] O'DoNOGHUE, Rambles in Raak. 21 



instituted, and, after attaining a depth of eight inches, the 

 gentle insertion of the blade of a pocket-knife into the hole 

 resulted in the prompt appearance of a dirty, moist, and 

 aggressive specimen of the so-called Bloodsucker, Amphibolurus 

 nturicatus. Henceforth we readily recognized the tunnels made 

 by this lizard, and made several futile efforts to establish the 

 identity of the species, as we thought, that made a larger, 

 though not so elongated, opening. At length we encountered 

 one whose Sv^il-heap was of more than the usual dimensions, 

 and after a considerable amount of scratching dead-ended our 

 quarry at a depth of eighteen inches — a large desert cockroach, 

 which, on being submitted with other insects collected during 

 the trip to Mr. J. A. Kershaw, Curator of the National Museum, 

 proved to be Geoscaphens rohustus. 



Stranger than either of the two exca\;ations mentioned was 

 the circular hole, about the diameter of a halfpenny, that went 

 down vertically, and had six or eight plugs of sand, from two 

 to three inches in length, neatly piled at its orifice. How these 

 had been piled upon one another ; by what means were they 

 formed ; by what creature ; and how had they been raised from 

 below, were questions more easily asked than answered. With 

 our fingers and a piece of wood we tried repeatedly, but un- 

 availingly, to solve the miner's identity. Early one morning, 

 having set out on an excursion of more than the usual radius, 

 we chanced upon one of these circular holes with an accom- 

 panying pile of fresh sand-plugs. With a pannikin we sank 

 a hole to the depth of three feet in the sandy loam before we 

 brought to light the object of our quest — a large brown beetle, 

 with a long, stout horn set in the middle of its head, and flanked 

 by two smaller ones. It proved to be one of the Digger Beetles, 

 Bolboceras sloanei. It would appear that, as the beetle delves 

 vertically with its powerful foreclaws, it forces the excavated 

 material upwards between its abdomen and the wall of the 

 shaft. When the burden above begins to incommode its 

 operations, it backs up the shaft, forcing the plug upwards till 

 it eventually topples over at the margin of the hole. However 

 plausible this explanation may appear, there is one fact that 

 seems to militate against its acceptance, and that is how each 

 successive plug raised from below falls directly upon the 

 previous one rather than elsewhere. The cohesion of the sand 

 appeared to be ensured by means of a mycelium, for some of 

 the fresh plugs examined were invested with a minute mesh, 

 v>^hich might possibly have been derived from the spinnerets 

 of some species of the spider tribe. 



The object, hereabouts, of the habit of making excavations 

 by the beetles and lizards, if not for the purpose of depositing 

 eggs, must be to make provision to withstand, like the dingo. 



