IV CERCERIS TUBERCULATA 53 



with their mandibles, and push out the heavy- 

 mass ; others scratch the walls of their tunnel with 

 the sharp rakes of their tarsi, forming a heap of 

 rubbish which they sweep out backward, and send 

 sliding down the steep incline in long dusty streams. 

 It was these periodical sand waves thrown out of 

 galleries in process of construction which betrayed 

 my first Cerceris, and led to the discovery of the 

 nests. Others, either weary, or having completed 

 their hard task, rested and polished their antennae 

 and wings under the natural caves which usually 

 protect their dwelling, or else sat motionless at the 

 mouth of their holes, only displaying their wide, 

 square faces, barred with yellow and black. Others 

 again were flying with a deep hum on the bushes 

 near the cochineal oak, where the males, always on 

 the watch near the burrows in process of construction, 

 speedily join them. Couples form, often troubled 

 ^3y the arrival of a second male, which tries to 

 supplant the happy possessor. The humming grows 

 menacing, quarrels begin, and often both males roll 

 in the dust until one acknowledges the superiority 

 of his rival. Not far off the female waits with 

 indifference the upshot of the struggle, accepting 

 finally the male bestowed on her by the chances of 

 the fight, and the pair fly out of sight to seek peace 

 in some distant thicket. Here the part of the male 

 ends. One half smaller than the females, they 

 prowl about the burrows but never enter, and never 

 take any part in the hard work of excavation, or 

 that perhaps yet harder of provisioning the cells. 



In a few days the galleries are ready, especially 

 as after some repairs those of the preceding year 



