214 NATURE SKETCHES IN TEMPERATE AMERICA 



particular interest, inasmuch as most all of the members of 

 this genus and its close allies are parasites, using the burrows 

 of other insects. Not infrequently they store their insect 

 prey in the deserted cells of a mud-dauber. Howard ^ relates 

 that there is a curious confusion sometimes in an Odynerus 

 wasp's cell, for a Trypoxylon wasp will enter one, carrying its 

 own store of food with it, and closing the entrance against the 

 return of the female wasp Odynerus; then comes along another 

 wasp, Crysis, and lays an egg, from which hatches a larva 

 which devours the stores of the wasp, Trypoxylon. 



In the present species, as I have shown, it has not become 

 parasitic like some of the allied species, but is a true nest 

 builder like Pelopwus. 



On August first, I found another mud-dauber's nest of a 

 distinct species cemented to the eaves of a house. I have 

 made an initial drawing of it, showing the underside of the 



cells, which are stored with sjiiders. 



In breaking the nest apart, the 



large white grub, with only two re- 



• ^^. - -^»>- maining spiders, fell out. The grub 



[•■:.' was just about ready to pupate. 



', ^ This nest contained seven cells. 



The Tabanid Fly as an Aerial 

 Performer 



HEX passing near a grove 

 of trees one evening in 

 August, I heard the hum- 

 ming sound of some in.sect. 

 I saw the winged minstrel 

 hovering, about the height 

 of my head, in one spot in mid-air. He remained suspended 

 for a moment, then darted off after a companion which was 

 similarly playing in the air. But back again he came after 

 each chase, as if this particular spot had some special attrac- 

 tion for him. I cautiously approached near enough to identify 

 him as a species of large Tabanid fly, Tabanus giganteus. 

 > "Insect Book," p. 32. 



