34 The Field Naturalist's Quarterly Feb. 



and down again to their resting spot, alighting head towards 

 the observer, and their silvery little faces glittering in the 

 sunlight like specks of polished metal. What is the meaning 

 and value of the metallic lustre that is far from uncommon 

 on the faces of Fossores ? Is it possible that it is a sexual 

 adornment, or does it help to make them conform somewhat 

 to their surroundings as they bask upon sandy soil with its 

 twinkling grains of quartz, or upon bare stone or rock glit- 

 tering with flakes of mica or similar crystalline minerals ? 



The domestic arrangements of the species under notice are 

 like those of its relatives already described. A burrow is 

 dug in the soil, rather firm clayey sand being preferred as 

 far as I have noticed, and into this burrow are carried two- 

 winged flies of many species. In my opinion O. uniglumis is 

 one of our chief insect benefactors in annually saving us from 

 plagues of flies. I have seen one individual take no fewer 

 than six flies into her burrow in the course of four minutes 

 and a few seconds, and the burrow when opened contained 

 sixteen flies all paralysed but alive, and only one larva of 

 Oxybelus — it is possible I may have overlooked some, but at 

 any rate a single individual can dig out a burrow in about 

 twenty to thirty minutes, and at the above rate get it amply 

 provisioned in about another twelve minutes — say. roughly, 

 thirty flies accounted for per hour by each individual : give 

 about five working hours per diem, 10 a.m. to 3 p.m., and 

 you have the very respectable total of 150 troublesome and 

 often biting flies put out of the way by each one daily. I 

 have never actually witnessed the capture of a fly by Oxybelus, 

 but have repeatedly seen both captor and captive fall pell- 

 mell to the ground together struggling violently ; in a very 

 few seconds the fly is reduced to impotence. I feel con- 

 vinced that the flies are captured in mid air while on the 

 wing ; certainly they are not taken while sitting on the 

 ground, for a few thrusts of the sting of Oxybelus quickly 

 puts a stop to the struggles of the fly, and it is not at all 

 likely that the fly would be carried through the air while 

 still in full vigour and the coup de grace deferred until it had 

 been brought within a foot or so of the burrow, for such is 

 the position in which I have always seen the above take 

 place. This species conveys the flies into the burrow in a 



