April, '07] ENTOMOLOGICAL NEWS. 137 



nests in the sand or clay, and, incidentally, be killed or eaten 

 by their larger or stronger neighbors. 



While collecting on one of these places in October, my 

 attention was attracted by the peculiar actions of a long-legged 

 fly which was running nervously over the ground. Its move- 

 ments were all quick and jerky, running three or four inches, 

 then stopping and spreading the wings out horizontally and 

 folding them over the back again, repeating the operation 

 several times in rapid succession, sometimes squatting low, 

 sometimes rising high on tip-toe. Sometimes it would fly short 

 distances, but always on alighting would go through these 

 same jerky movements. Now and then, in its running about, 

 it would come close enough to one of the little Agromyzids 

 (Rhicnocssa panntla Lw.), that were quite abundant here, 

 to pounce upon it and suck its blood. The unfortunate little 

 fly is held and manipulated by the fore-legs of its captor, and 

 after being turned over a few times, evidently in order that 

 the blood may be sucked from different parts, the empty skin 

 is dropped to the ground and blown away by the wind, while 

 the vampire goes in search of another morsel. 



While watching one of these flies, which proved to be a 

 female, she seemed suddenly to become very much excited, 

 now squatting low, now rising high and waving the wings 

 frantically. The cause of this extra excitement was a male 

 fly which, unnoticed by me, had approached to within a few 

 inches of the female. He seemed to be paying but little 

 attention to her, but was running about much as she had before 

 he appeared. He gradually worked near her, however, and 

 for some little time they stood facing each other, going through 

 the curious performance of raising and lowering their bodies 

 and waving the wings frantically. The male then turned 

 away and seemed about to leave, but the female quickly flew 

 in front of him again and began her antics. Several times 

 this was repeated, the male sometimes flying away for a con- 

 siderable distance; but whenever he came near the female, 

 again she would run in front of him and begin waving her 

 wings. Finally the female flew directly to the male, and I 

 think that copulation took place, although I could not tell 



