618 DESCRIPTIONS OK PLATES. 



tica! spots, b b, The central paler horny plate, c, The raised margin of the 

 true aperture, d d, Branches of trachea. Figs. 5 11, Ovipositor of Sirex 

 juvencus. 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, b, projects from the two valves, a. Fig. 7, Apex 

 of the ovipositor, seen from above, c, The divided dentate apex of the sheath. 

 d d, The two dentate seta? within the sheath. Fig. 8, The ovipositor, from the 

 side, c, The upper channel, rf, The single lower seta. Fig. 9, From beneath, 

 c c, Sheath, d d, Setae. Fig. 10, One seta, to exhibit the shape of the teeth 

 upon it. Fig. 1 1 , Transverse section of the ovipositor, a a, The external 

 valves, c, The sheath, d d, The setae, e, Central free channel. Figs. 12 14, 

 Ovipositor of Pirnpla. 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 quercifolia. Fig. 15, Last bent segment, with 

 the two hairy processes originating from the internal surface. Fig. 16, 

 The ovipositor, a a, Valves, b b, External channel of the setse. c, Central 

 finer seta. Fig. 17, The external, b b, and the central seta, c, alone. 

 Fig. 18, Section, a a, Valves, b b, External setae, e, Central one. 



PL XXIV. Figs. 17, Ovipositor of Cicada Fraxini. Fig. 1, Apex of 

 abdomen. A, Last dorsal segment. D, Last ventral segment. B, Basal 

 joint of the sheath of the ovipositor. C, Terminal joint. Fig. 2, Ovipositor 

 with the valves from beneath. B B, Basal joints of the valves. C C, Terminal 

 joints. D, The ovipositor. Fig. 3, Apex of the ovipositor from beneath, 

 a a, Superior distended sheath, with teeth on the margin, b 6, The lower setae 

 pushed upwards, so that they project beyond the apex of the sheath. Fig. 4, 

 Setae from the inner side, 10 show the central channel. Fig. 5, Apex of the 

 sheath from above, toothed on the margin, furrowed in the centre, emarginate 

 at the apex to receive the points of the setae, which form the true apex of the 

 ovipositor. Fig. 6, Section, a a, The valves, b b, The sheath, c, The setee. 

 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, or 

 saws, c, Central short process. Fig. 9, An internal valve, or saw, from its 

 external surface, b, Furrow, by means of which the external surface is divided 

 into two halves. <z, Lower more finely serrated, b, Superior more coarsely 

 serrated surface. Figs. 10 15, Ovipositor of Locusta. Fig. 10, Apex of the 

 abdomen of Locusta viridissima. A, Last dorsal segment. B, Last ventral 

 segment. C, Ovipositor. Fig. 11, One half of the sheath seen from the 

 exterior of Locusta ephippiffer. Fig. 12, The same from the inner surface. 

 o, Superior half of the valve, c, Lower half. f>, Central, smaller, inner valve 



