116 Annals Entomological Society of America [Vol. IV, 



Chirotonetes albomanicatus Needham. 

 Occurrence, habitat. Nymphs of this abundant species 

 were found full grown in the dashing waters of the falls and riffles 

 from the latter part of May to August 12th. In May they were 

 seen to emerge in greatest numbers during the late afternoon 

 and twilight. They crawled up on the shore leaving their cast 

 skins clinging to the stones or less often they flew up directly 

 from the mid current. The dark wings and body and the white 

 forelegs of the sub-imago made it very conspicuous as it rested 

 upon the gray stones or flew upward. Robins made a regular 

 custom of coming to the shores and collecting the insects as they 

 emerged. From four to six nymphs might be often seen pro- 

 jecting from their beaks. 



Siphlurus alternatus Say. 

 This elegant species has been found to be very desir- 

 able for the indoor aquarium. It lives in still pools and 

 demands only a minimum supply of fresh water and plenty of 

 plant food. It was common all through April, May, and a 

 portion of June. Nymphs kept in the laboratory aquarium 

 nearly all lived to emerge and doubtless could have been kept 

 there several months had they been taken early enough. 



Baetis pygmea Hagen. 



This species has been found chiefly interesting for its habits 

 of egg-laying. From early June to late August the stones in the 

 waters of the creek were covered with small elongate egg- 

 patches rounded at one end, narrower and sharply squared off 

 at the other. Plate XII, fig. 1 shows a stone about seven by 

 ten inches in size on which the egg masses were scattered with 

 average abundance. The surface upon which the eggs rested 

 was the down-stream side of the stone and that portion where 

 they were thickest was nearest to the surface of the water. On 

 the same plate (fig. 2) is shown a photograph in which the 

 patches are enlarged sufficiently to show the individual eggs. 

 The laying of the eggs may be seen if one closely watches some 

 stone which is marked as a favorite site by the presence of many 

 masses. The following observation was made through an ordi- 

 nary reading glass, but the processes may be easily seen with 

 the naked eye. 



Flying close to the surface of the water, the insect alighted 

 on a stone projecting slightly from the water and well protected 

 from the force of the current on its downstream side. She 



