WASPS THAT PREY ON BEETLES 131 



we have never been able to catch them doing anything that 

 would explain the mystery of this lazy flight, with an occa- 

 sional disappearance into the weeds. This place must have 

 been in some way peculiarly adapted to their needs or liking, 

 for while they were plentiful here they were never seen more 

 than one hundred feet away. 



Since they lingered persistently near stable-waste, and 

 since Scotia's young are known to feed upon beetle larvae, we 

 suspected they were there because the manure-heaps fur- 

 nished the habitat for their prey. Examination of the man- 

 ure heaps revealed hundreds of larvae, probably Co tints 

 nitida Linn., large, medium and small. A half-dozen Scolia 

 dubias were also seen flying about in the same place. We 

 spread the manure attractively and waited an hour, but saw 

 none of the wasps oviposit therein. We took a large number 

 of the beetle larvae home, hoping to rear from them adult 

 S. dubias, but never found any evidence of their being so 

 infested. 



Many long vigils were spent at this place, but the summer 

 came to a close without our having been able to learn one 

 whit beyond mere conjectures of the reasons for their mys- 

 terious flight and their presence in this spot. 



The following year we early began our watch around the 

 site, in an effort to solve some of the mysteries of their 

 presence there, but they did not appear until August 19. We 

 could not tell whether they emerged en the spot, or came 

 to it. This year as previously, they occurred only in the 

 limited area where foul horse-bedding was piled near the 

 stable. Most of the weeds were this year supplanted by 

 sun-flowers. Here about the flowerheads were ten 5\ dubias, 

 flying about in the same meaningless manner as before, 

 resting occasionally for long periods. They have the great- 

 est propensity for resting that we have ever witnessed in 

 the wasp world. One flew about for only a few seconds 



