85 



common than spiiu'rejjs or extennis at the mouth of Quiver 

 Creek, but in the main channel of the Illinois below Spoon 

 River they were the most abundant form. Nymphs have also 

 been taken in Quiver and Matanzas lakes, in the Illinois River 

 at Meredosia, and in Spoon River near Bernadotte, 111. Ex- 

 amples of this species and externus taken in June and placed in 

 breeding-cages immersed in the water along the Quiver Lake 

 shore, remained alive without transformation until the season's 

 work closed at the end of September. This species is very close 

 to G. notafiis, which is comparatively rare in Illinois, and the 

 nymph of which has not been satisfactorily distinguished from 

 that of plagiatus. 



The first transforming imago was noted May 21. On July 

 2, 1894, large quantities of nymphs transformed in the early 

 morning upon the piers of the river bridges. Upon arriving in 

 Havana in the latter part of June, 1897, Mr. Hart found the 

 imagos emerging numerously up to about the end of the 

 month. In 1898 the largest number emerged June 21, and 

 thereafter occasionally up to June 30. Mr. Needham's notes, 

 made while at Havana in July, 1896, are as follows: 



" Transformation takes place mostly at night, but not un- 

 commonly late in the afternoon. The nymph crawls a little 

 way (3 to 20 inches) out of the water upon any flat surface. I 

 have found exuviae sticking to bridge piers and to the sides of 

 barges and fishing boats, to willow stumps, and to bare mud 

 banks. I obtained hundreds of nymphs and exuviae, and yet 

 during a month spent upon the river collecting I did not see a 

 single imago of this species on the wing. I captured one newly 

 emerged, at dusk, resting in the grass at the bank ; no others 

 were obtained except by rearing them. Consequently, no op- 

 portunity was found for studying breeding habits and ovipos- 

 ition." 



Kellicott also notes the emergence on piling and walls in 

 deep water, and found the imago "resting on coarse grasses 

 during July. None were seen ovipositing, or flying except to 

 escape from danger." 



