WASPS, SOCIAL AND SOLITARY 



cases in which there was no such anxiety about the 

 size of the nest, there was, in reality, more reason for it. 

 Indeed, in one instance the opening had to be enlarged 

 before the spider could be taken in. There is a wide- 

 winged parasitic fly that, having nothing else to do, lays 

 prodigious numbers of eggs, not in any particular nest, 

 but at the edge of holes wherever it may chance to see 

 them. It hovers about over the ground until it comes 

 to an opening, dips down twice or thrice, ovipositing 

 each time, and then passes along. The habit of scratch- 

 ing out a little dirt at the threshold, just before the prey 

 is brought in, seemingly from a desire to enlarge the 

 nest, or in other cases from mere nervousness, is per- 

 haps of use in destroying these eggs, which might other- 

 wise adhere to the spider or caterpillar as it is dragged 

 over them. 



The laying of the egg takes only two or three minutes, 

 and then the hole is filled up. In this part of her work 

 quinquenotatus shows a great deal of variation, some- 

 times coming out of the hole and sweeping in the dirt 

 with her first legs and sometimes standing in the tunnel 

 while she draws the earth in with her mandibles and 

 then jams it down with the end of her abdomen. The 

 former plan was in vogue in the garden, while the latter 

 was more common with the wasps on the island. After 

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