62 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



time of day. In view of this paucity of information I was 

 much pleased when opportunity came to observe these neg- 

 lected insects. 



An entomological excursion, on September 19, 1908, led me 

 up the Potomac to Cabin John, Maryland. Rather late in the 

 afternoon, emerging from the woods to the banks of the old 

 Chesapeake and Ohio Canal, I came upon a luxurious growth 

 of Verb esina alterni folia (.L,.) Britt., a yellow-flowered com- 

 posite, then in full bloom. Frightened by my sudden ap- 

 proach, two small Tipulidae rose from the flower-heads and 

 hovered in the air above them, evidently reluctant to leave. 

 They soon returned to their respective flower-heads and, af- 

 ter executing for a time a curious, very rapid, vibrating move- 

 ment by swinging upon their long, slender legs, they probed 

 eagerly into the florets. They were captured without diffi- 

 culty and proved to be a male and female of Getanomxia cana- 

 denis West wood. 



The past season I visited the same patch of Verbesina again, 

 on September 18, and was gratified to find Geranomyia pres- 

 ent in considerable numbers. It was about 4.30 in the after- 

 noon and the sun was already low. At first there were but a 

 few individuals present upon the flowers, very busily probing- 

 for honey. As the sunlight faded their number increased, so 

 that soon there were several upon every plant, sometimes two 

 or three on one flower-head. They would first hover ner- 

 vously over the flower for a brief period, then descend upon 

 the flower and for a short interval go through the curious vi- 

 brating movement, and finally begin work upon the flowers in 

 the most eager manner. They would walk about upon the 

 flower-heads and plunge the proboscis deep into a floret 

 and, after a brief interval, withdraw it and insert it in another; 

 repeating this many times, each time with a new floret. I 

 watched the insects for a full hour and saw hundreds of them 

 within a radius of ten or fifteen feet. The precision with 

 which they sought the nectar showed very clearly that the 

 habit was well fixed. All belonged to one species, Gerano- 

 myia canadensis, and both sexes were represented in about 

 equal numbers. 



It was now evening and growing cool and I turned home- 

 ward. In passing through a glade beside a stream I found a 

 number aiGeranomyia upon the flower-head of an Eupatorium 

 purpureum L-, growing at the edge of the thicket. Here two 

 species of Geranomyia were present; in addition to the species 

 already observed, and outnumbering it, was G. rostrata Say. 



