The Hunting Wasps 



from these tactics and those adopted in a Hke 

 case by the Cricket-hunters. Why that 

 domicihary visit which invariably precedes 

 the entrance of the game? Could it not be 

 that, before descending with a cumbrous bur- 

 den, the Sphex thinks it wise to take a look 

 at the bottom of her dwelling, so as to make 

 sure that all is well and, if necessary, to drive 

 out some brazen parasite who may have 

 slipped in during her entrance? If so, who 

 is the parasite? Several Diptera, Predatory 

 Gnats, especially Tachinae, watch at the doors 

 of the Hunting Wasps, spying for the pro- 

 pitious moment to lay their eggs on others' 

 provisions; but none of them enters the home 

 or ventures into the dark passages where the 

 owner, if by ill-luck she happened to be in, 

 would perhaps make them pay dearly for 

 their audacity. The Sphex, like all the rest, 

 pays her tribute to the plundering Tachinae; 

 but these never enter the burrow to perpe- 

 trate their misdeeds. Besides, have they not 

 all the time that they need to lay their eggs 

 on the Cricket? If they are sharp about 

 it, they can easily profit by the temporary 

 abandonment of the victim to entrust their 

 progeny to it. Some greater danger still 

 must therefore threaten the Sphex, since her 

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