Thrasymedes Kirkaldy

Figs 18-22

Nymph diagnosis.

Body densely setose; with full complement of paired dorsal scoli from head to abdominal segment IX (12 pairs in total), though slender, not long and without stalked chalazae; abdominal segment IX as long as combined length of remaining abdominal terga; abdomen without scoli ventrolaterally.

Nymph description.

Overall body. Fifth instar length 8.5 mm. Cross-section subtriangular; thorax and abdomen densely covered with chalazae, distinct throughout body; chalazal setae long; scoli parallel. Head. With simple conical scoli, directed anterad; chalazal bases long-stalked; compound eye surface with setae; enlarged chalazae between eyes present as pair of vertical rows; setae of frontoclypeus dense; scoli length about 5-7 × basal width; enlarged chalazae in front of ventral margin of eye present; enlarged chalazae adjacent to central or dorsal margin of eye present; frons not extending over central margin of eye. Prothorax. Premetopidium scoli present, directed dorsoanteriorly; postmetopidium scoli present, directed anteriorly; posterior extension of pronotum surpasses anterior margin of metanotum, but does not attain1 its posterior margin; premetopidial scoli length about 5-7 × basal width; postmetopidial scoli length about 5-7 × basal width. Mesothorax. Dorsal scoli bearing stalked chalazae; scoli directed dorsoanteriorly and length about 5-7 × basal width; anterior basal side of scoli lacking cluster of enlarged chalazae; forewing pad anterior costal margin straight; forewing pad surface densely covered by long chalazae; forewing pad costal chalazae along entire costal margin; lateral rows, if present, most medial row extending unto meso- and metathorax. Metathorax. Scoli bearing stalked chalazae; scoli directed dorsally or almost so; dorsal scoli length about 5-7 × basal width. Legs. Chalazae of tibia present on both lateral margins and dorsal surface; prothoracic tibia form subcylindrical. Abdomen. Terga III-VIII ventrolateral margins each with 3 enlarged chalazae; terga III-VIII dorsal scoli length subequal to each other and bearing stalked chalazae; terga III-VIII tallest dorsal scoli length about 5-7 × basal width; tergum IV dorsal scoli preapically directed dorsally or almost so, apically dorsoposteriorly; terga III-VIII bearing 1 lateral row of slightly enlarged chalazae; lamellae absent. Segment IX: longer than combined length of remaining abdominal terga, but shorter than length of rest of body; preapically with dorsal surface irregularly covered in chalazae.

Material examined.

Thrasymedes pallescens ( Stål): 39 adults, 1 nymph, 4 5th instar exuviae, Mexico: Michoacán, Route 150, km 270, 40 km E Panindicuaro, 2150 m elev., 19°52'55"N, 101°24'45"W, 9 November 2001, S.H. McKamey leg. (USNM) .