84 INSECT LIFE vi 



in search of game, and take a look at her dwelling. 

 The spot chosen by a Sphex colony is generally 

 horizontal, though the ground is not so level but 

 that there are little mounds crowned by a tuft of 

 grass or thrift, or inequalities consolidated by the 

 slender roots of the vegetation which covers them. 

 It is on the sides of such furrows that the Sphex places 

 her den. For two or three inches in depth the gallery 

 is horizontal, serving as an approach to the hidden 

 shelter for the provender and the larvae. In this vestibule 

 the Sphex takes refuge in bad weather, rests there at 

 night, and occasionally by day for a few instants, 

 showing only her expressive face and impudent 

 eyes. Beyond the vestibule an abrupt turn descends 

 more or less obliquely to a depth of two or three 

 inches more, ending in an oval cell rather larger 

 in diameter, whose axis lies parallel with the 

 horizontal gallery. The cell walls are not covered 

 with any particular cement, but in spite of their 

 bareness they have evidently been the object of most 

 careful labour. The sand is heaped and levelled on 

 the floor, on the ceiling, and sides, so as to do away 

 with the risk of landslips, or any roughness which 

 might injure the delicate skin of the larva. This 

 cell communicates with the passage by a narrow 

 entrance, just wide enough to allow the Sphex, 

 burdened with prey, to enter. When this first cell 

 is furnished with an egg and necessary provisions, 

 the Sphex walls up the entrance, but does not yet 

 abandon her burrow. A second cell is hollowed 

 beside the first, and provisioned in the same manner ; 

 there is then a third made, and sometimes a fourth. 

 Only then does the Sphex cast back into the 



