618

DESCRIPTIONS OF PLATES.

tical spots, b b, The central paler liorny plate, c, The raised margin of thetrue aperture. <1 d, Branches of trache ®. Tigs. 5—11, Ovipositor of Sirexjuvencus. Fig. 5, Last abdominal segment, with the ovipositor, A. B B,Lateral margins of the last largest segment. Fig. 6, Apex of the abdomen,from the side. The ovipositor, 6, projects from the two valves, a. Fig.7, Apexof the ovipositor, seen from above, c, The divided dentate apex of the sheath.d d, The two dentate set® within the sheath. Fig. 8,The ovipositor, from theside, c, The upper channel, d, The single lower seta. Fig. 9 , From beneath.c c, Sheath, d d, Set®. Fig. 10, One seta, to exhibit the shape of the teethupon it. Fig. 11, Transverse section of the ovipositor, a a, The externalvalves. c,Thesheath. d d, The set®, e, Central free channel. Figs.12—14,Ovipositor of Pimpla. Fig. 12, Apex of the organ, covered with short teeth,a, The upper channel, b, The fine seta. Fig. 13, Section of the mere ovi-positor. a, Channel, b, Seta. c, Canal . Fig. 14, Section of the ovi-positor, with the valves. a, Channel, b, Seta, cc, Valves, e, Canal . Figs.15—18, Ovipositor of Cynips quercifulia. Fig. 15, Last bent segment, withthe two hairy processes originating from the internal surface. Fig. 16,The ovipositor, a a, Valves, b b, External channel of the set®, c, Centralfiner seta. Fig. 17, The external, b b, and the central seta, e, alone.Fig. 18, Section, a a, Valves, b b, External set®, e, Central one.

PL XXIV. Figs. 1—7, Ovipositor of Cicada Fraxini. Fig. 1, Apex ofabdomen. A, Last dorsal segment. D, Last ventral segment. B, Basaljoint of the sheath of the ovipositor. C, Terminal joint. Fig-2, Ovipositorwith the valves from beneath. B B, Basal joints of the valves. C C, Terminaljoints. D, The ovipositor. Fig. 3, Apex of the ovipositor from beneath.a a, Superior distended sheath, with teeth on the margin, b b, The lower set®pushed upwards, so that they project beyond the apex of the sheath. Fig. 4,Set® from the inner side, to show the central channel. Fig. 5, Apex of thesheath from above, toothed on the margin, furrowed in the centre, emarginateat the apex to receive the points of the set®, which form the true apex of theovipositor. Fig. 6, Section, a a, The valves, b b, The sheath, c, The set®.Fig. 7, Section of the mere ovipositor, a a, Sheath, b, Seta. Figs. 8, 9,Ovipositor of Cimbex variabilis. Fig. 8, The valves opened from beneath.A A, The last dorsal segment, a a, External valves, b b, Internal valves, orsaws, c, Central short process. Fig. 9 , An internal valve, or saw, from itsexternal surface, b, Furrow, by means of which the external surface is dividedinto two halves, a, Lower more finely serrated, b, Superior more coarselyserrated surface. Figs. 10—15, Ovipositor of Locusta. Fig. 10, Apex of theabdomen of Locusta mridissima. A, Last dorsal segment. B, Last ventralsegment. C, Ovipositor. Fig. 11, One half of the sheath seen from theexterior of Locusta ephippiyer. Fig. 12, The same from the inner surface,a, Superior half of the valve, c, Lower half, b, Central, smaller, inner valve