. Bulletin. Natural history; Natural history. 94 ILLINOIS NATURAL HISTORY SURVEY BULLETIN \"ol. 21, Art. 3 Pionotuiii about twice as wide as long, ail angles well rounded; fringed with numerous small setae and occasional long ones, marginal groove well developed (jn anterior and posterior margins but absent on lateral margins. Mesonotum with wing pads extending almost straight backwards, those on metanotum extending slightly out- \xard. Legs very little flattened; hind margins of femora, tibiae and tarsi with a fringe of long fine setae ; femora with a narrow dark band before apex. Cerci
. Bulletin. Natural history; Natural history. 94 ILLINOIS NATURAL HISTORY SURVEY BULLETIN \"ol. 21, Art. 3 Pionotuiii about twice as wide as long, ail angles well rounded; fringed with numerous small setae and occasional long ones, marginal groove well developed (jn anterior and posterior margins but absent on lateral margins. Mesonotum with wing pads extending almost straight backwards, those on metanotum extending slightly out- \xard. Legs very little flattened; hind margins of femora, tibiae and tarsi with a fringe of long fine setae ; femora with a narrow dark band before apex. Cerci long, many segmented, segments progressively longer apically, distal half with a row of long fine setae on dorsal surface in addition to shorter ones en- circling segments. Approximately mature specimens with a body length, exclusive of appendages, of about 15 mm. Submental, thoracic and abdominal gills entirely lacking. Nymphs. British Columbia.—Cultus lake, .Sweltzer creek: March 28, 1937, W, E. Ricker; April 24, 1935, cast skins; Reservoir creek, May 30, 1935, W. E. Ricker, cast skins. Isoperla truncata—new species MALE.—Dominant color a pale whitish vellow with some light brown and dark mai kings. Head, fig. 83, mostly pale whit- ish vellow; compound eyes and area im-. Fig. 83.—Isoperla Irnncalii. mediatel)- surrounding ocelli black; lateral ocelli connected with median ocellus by short dark brown stripes which connect with a large solid transverse quadrate brown patch adjacent to median ocellus. Prothorax mostly pale whitish yellow with two longitudinal brown stripes, particu- larly accentuated in depth of brown at anterior margin; dorsum of meso- and metathorax mostly pale brown. Abdomen pale with weakly indicated brownish median and lateral longitudinal stripes on dorsum. Antennae, cerci and most of legs pale brown. Head much wider through compound eyes than pronotum; three ocelli forming a nearly equilateral triangle, lateral ocelli placed on a line slightly ant
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Keywords: ., booka, bookcentury1900, bookdecade1910, booksubjectnaturalhistory
