Allocapnia mystica Frison, 1929

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 : 11-16

Allocapnia mystica Frison

Allocapnia mystica Frison (1929) . Holotype ♂, Salt Fork River, Oakwood , Illinois

Allocapnia mystica: Frison (1929) and Claassen (193l), larval description

Distribution. AL, AR, GA, IL, IN, KY, MO, MS, OH, TN, VA, WV ( Stark 2001). Mississippi, populations have been reported in Lauderdale, Pontotoc, Union, and Webster counties ( Stark 1979). New records are given for Clarke, Lowndes and Tishomingo counties. Material examined. Mississippi: Clarke Co., Rock Creek, Hwy. 18, 18 December 2002, 3 ♂, B. Stark, J. Lacey. Lowndes Co., Mayhew Creek , Hwy. 12, 29 December 1998, 7♂, B. Stark. Tishomingo Co., Little Cripple Deer Creek , Hwy. 957, 4 January 2000, 12 ♂, B. Stark, M. Alford. Webster Co., Line Creek , Hwy. 15, 3 January 2000, 22 ♂, 8 ♀, B. Stark, M. Alford. Same location, 27 December 2002, 15 ♂, 6 ♀, 30 larvae, B. Stark.

Male genitalia. Dorsal arm of epiproct bent near midlength; apical half slightly wider than base and swollen before the attenuated apex; surface sparsely armed with posteriorly directed spines ( Figs. 7-8 ). Dorsal process of tergum 8 narrowly notched on thin anterior ridge and developed into a large flat posterior plateau behind ridge ( Fig. 9 ).

Pre-emergent larva. Body length 6.5-8.0 mm. General body color pale brown to tan, without distinctive pattern. Metanotal ( Fig. 10 ), cercal ( Figs. 11-12 ), mandibular, lacinial and labral setation ( Fig. 13 ) typical of genus; galea armed on apex with a few acute spines; outer margin of galea without fringe of long setae ( Fig. 14 ). Developing lobe of male tergum 10 distal to cercal bases about twice as long as tergum length proximal to cercal bases ( Fig. 15 ); dorsal margin of developing male long and straight; posterior margin truncate in lateral aspect.

Abdominal terga sparsely covered with clothing hairs and decumbent bristles; erect bristles restricted to posterior tergal margins ( Fig. 16 ); longest erect bristles about 0.4 times as long as tergum.

Diagnosis. The absence of erect tergal bristles at midlength ( Fig. 16 ) will distinguish larvae of this species from all but those of A. aurora among Mississippi species. The truncate posterior margin of the developing male 10 th tergal lobe ( Fig. 15 ) will distinguish these species.

Figures

Figs. 7-12. Allocapnia mystica. 7. Male epiproct. 8. Apex of epiproct. 9. Male 8th tergal process. 10. Larval left metanotal wingpad. 11. Basolateral aspect of larval cercal segments. 12. Apicolateral aspect of larval cercal segments.

Figs. 13-16. Allocapnia mystica. 13. Ventral aspect of larval head. 14. Ventral aspect of left galea. 15. Lateral aspect of larval male 10th tergum and basal cercal segments. 16. Lateral aspect of abdominal terga 6-7. (Ga = galea, Gl = glossa, Lc = lacinia, Lp = labial palp, Mp = maxillary palp, Pg = paraglossa)