42 



of Lake Geneva, Wisconsin, within ten miles of the Illinois 

 line, September 2 and 5, about the summer resort cottages and 

 along the lake shore. In New York it has been taken from 

 August 28 to September 22 ; in Nova Scotia, July 26. Cabot 

 described and figured ('81, p. 23; PI. II., Fig. 2) a nymph 

 taken at the same time and place as imagos determined as 

 v^. " eremificff,'' and assigned it by supposition to that species. 

 E/riiiifica is an erroneous writing of eremifa, which h a syno- 

 nym of clepsyd}'a. 



The nymph of clrpsydra differs from all other known 

 ^schna nymphs in having recognizable lateral spines on the 

 fifth abdominal. It is otherwise similar to eonsfrtcta, and may 

 be distinguished especially by the following characters given 

 by Cabot ('81, p. 37) from full-grown nymphs of both sexes 

 from Hermit Lake in New Hampshire, mouth of Red River of 

 the North, and Minnesota: " Hind angles of head oblique, proc- 

 esses long, equal, sharp, tips bent a little outwards, inclosing 

 less than a right angle ; lateral appendages two thirds the 

 length of the middle one ; female valves not quite reaching tip 

 of segment." 



2. ^-EscJnta roHsfrirffi Say. 



This is one of our more common dragon-flies, appearing on 

 the wing in Illinois after midsummer, and disappearing only 

 with the autumnal frosts. It ranges over the entire northern 

 part of the United States, and from Labrador into Siberia, 

 being apparently less common throughout the Mississippi 

 valley than on the north Atlantic and north Pacific slopes. 

 The Illinois specimens are from various localities in the cen- 

 tral and northern parts of the state. Van Duzee ('97) found 

 it most abundant along the meanderings of small brooks in 

 hilly country. 



Our nymphs were collected in a small ditch at the west 

 end of Lake Geneva, Wisconsin, in August, and from a little 

 streamlet in the Mississippi bluffs near Savanna, Illinois. We 

 also have a half-grown nymph from Pine Lake, near Charle- 



