248 ■ Annals Entomological Society oj America [Vol. IX, 



Calliopsis nebraskensis Cwfd. [J. C. Crawford]. 

 On August 7, when it was nearly dark, I opened a nest of 

 this little bee. She was near the top and I suspect she was still 

 at work for some of the loose soil on top of the mound at the 

 mouth of the burrow seemed quite fresh. 



Chrysis perpulchra Cress. [vS. A. Rohwer]. 

 These beautiful green cuckoo-bees are very conspicuous near 

 the top of the Erigeron at about the height of a man's shoulder 

 or eye, where they settle to rest in the late afternoon. As long 

 as the daylight lasts, however, when they may still be seen, they 

 are too alert to be in any danger of being captured; only when 

 covered by darkness are they helpless. They usually wrap 

 their tiny bodies horizontally about the small vertical stem or 

 petiole of the leaves or flowers. They probably return to the 

 same sleeping quarters night after night, for I found them on 

 the same clump of plants on three successive nights. 



FLIES 

 Proctacanthus milberti Macq. [F. Knab]. 



Robber flies have a most tantalizing way of evading capture ; 

 as one draws near them they remain alluringly motionless until 

 one brings down the stroke intended for their capture; at that 

 instant they fly away with a loud buzz only a short distance and 

 alight again to tempt one and repeat the performance. In the 

 evening they behave in much the same way when approached 

 until twilight is far advanced, when they relax into deep sleep 

 at about 8 o'clock, resting on the vegetation at a height of about 

 three feet from the ground, and may be picked up with perfect 

 ease. Their night position is not different from that of the day, 

 but the feet automatically grip the support firmly. Whenever 

 taken, whether awake or asleep, they always exude from the 

 anus a drop of brown, pasty substance; I do not know whether 

 this is the normal function of excretion or some special means of 

 protection to ward off the attacks of enemies. 



A pair of these robber-flies in copula were watched at Lake 

 View, Kansas, August 18, at 7 o'clock in the evening. These 

 two followed the same tactics of resting and flying for short 

 distances when pursued. 



