. Bulletin. Natural history; Natural history. Figs. 270-273.—Terminal abdominal segments and geniialia of Plcronarrys nobilis. 270.—Latenil view of male. 271.—Dorsal view of male. 272.—Ventral view of male. 273.—Ventral view of female. The adults begin emerging in Illinois in April and a few are still emerging during the first days of June. A female with eggs has been taken at Rock Island on June 3. The nj^mphs of nobilis are not found in Illinois in the small creeks and brooks, which are capable of sustaining certain Allocapnia, Neinoura and Leuctra. Instead they are found in the medium sized
. Bulletin. Natural history; Natural history. Figs. 270-273.—Terminal abdominal segments and geniialia of Plcronarrys nobilis. 270.—Latenil view of male. 271.—Dorsal view of male. 272.—Ventral view of male. 273.—Ventral view of female. The adults begin emerging in Illinois in April and a few are still emerging during the first days of June. A female with eggs has been taken at Rock Island on June 3. The nj^mphs of nobilis are not found in Illinois in the small creeks and brooks, which are capable of sustaining certain Allocapnia, Neinoura and Leuctra. Instead they are found in the medium sized rivers such as the Embarrass, fig. 13, and the largest rivers such as the Rock, fig. 269, and Mississippi. The nymphs apparently prefer some riffle in the stream where they can cling to submerged decaying objects, such as blanches or trunks of trees which tend to lodge in such places, or where they can be covered with a finer debris of twigs and old leaves. Our records for the various sizes of the nymphs are indicative that it requires about two years for development from egg to adult. Examinations of stomach contents show the nymphs to be herbivorous, a type of feeding indicated by their mouthparts. The adult terminal abdominal segments and genitalia are shown in figs. 270-273. Since the nymph has not been previously recognized, a description of its most important features Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Illinois. Natural History Survey Division. Urbana, State of Illinois, Dept. of Registration and Education, Natural History Survey Division
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