Allocapnia aurora Ricker, 1952

Stark, Bill P. & Lacey, Joe W., 2005, Larvae Of The Winter Stonefly Genus Allocapnia (Plecoptera: Capniidae) In Mississippi, Usa, Illiesia 1 (3), pp. 10-20 : 11

Allocapnia aurora Ricker

Allocapnia aurora Ricker (1952) . Holotype ♂, Pigeon River, Woodrow , North Carolina

Distribution. AL, DC, GA, MD, MS, NC, PA, SC, TN, VA ( Stark 2001). Mississippi populations have

been reported from Amite, Franklin, Lauderdale and Tishomingo counties ( Alford 1998; Stark 1979). A new record is given for Clarke County.

Material examined. Mississippi: Clarke Co., Little Okatuppa Creek , Hwy. 18, 7 December 2002, 2 ♂, 22 larvae, B. Stark. Same location, 18 December 2002, 19 larvae, B. Stark, J. Lacey. Same location, 29 December 1999, 1♀, B. Stark. Same location, 18 January 2003, 1♂, 4 larvae, B. Stark, W. Hawkins, S. Cope. Same location, 8 January 2005, 1♂, B. Stark .

Male genitalia. Previously described from scanning electron micrographs by Alford (1998). Dorsal arm of epiproct bent near midlength, apical shape similar to a spear point; apex of dorsal limb engraved with a pattern of smooth, scalloped ridges ( Figs. 1-2 ). Dorsal process of tergum 8 deeply divided by a wide Ushaped notch; tergum 7 with an obscure mound shaped process near anterior margin.

Pre-emergent larva. Body length 6.0-7.5 mm. General body color pale brown to tan, without distinctive pattern. Mandibles, laciniae and labium ( Fig. 3 ) typical of genus; galea armed on apex with a few acute spines; outer margin of galea without fringe of long setae ( Fig. 4 ). Developing lobe of male tergum 10 distal to cercal bases more than twice as long as tergum length proximal to cercal bases ( Fig. 5 ); dorsal margin of developing male lobe straight but with slight subapical elevation; posterior margin slanted in lateral aspect. Abdominal terga sparsely covered with clothing hairs and decumbent bristles; erect bristles restricted to posterior tergal margins ( Fig. 6 ); longest erect bristles about 0.4 times as long as tergum.

Diagnosis. The presence of erect bristles only on the posterior margins of abdominal terga ( Fig. 6 ) will distinguish nymphs of this species from all those occurring in Mississippi except A. mystica . In that species the posterior margin of the developing male 10 th tergal lobe is truncate in lateral aspect rather than slanted ( Fig. 5 ).

Figures

Figs. 1-6. Allocapnia aurora. 1. Male terminalia. 2. Apex of epiproct. 3. Ventral aspect of larval head. 4. Ventral aspect of left galea. 5. Lateral aspect of larval male 10th tergum and basal cercal segments. 6. Lateral aspect of abdominal terga 8-9. (Ep = epiproct, Ga = galea, Gl = glossa, Lp = labial palp, Mp = maxillary palp, Pg = paraglossa)