85 
common than spiniceps or externus 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, Il. Ex- 
amples of this species and exrternus 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. notatus, 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 exuvie sticking to bridge piers and to the sides of 
barges and fishing boats, to willow stumps,and to bare mud 
banks. | obtained hundreds of nymphs and exuvie, 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.” 
