ZOOLOGY AND BOTANY, MICK08C0PY, ETC. 63 



clear that they were not parasitic in the cells of subterrestrial 

 Hymenoptera. The particular species of Orthopteron is of slight 

 importance so long as the eggs are in sufficient quantity and can be 

 easily attacked by the mandibles ; the AcrididaB best conform to these 

 conditions. 



Proboscis of Hemiptera.* — Herr H. Wedde adds to the numerous 

 recent researches on the oral organs of insects a careful investigation of 

 those of the Bhynchota, or Hemiptera in the wider sense. He analyses 

 the jointed rostrum of those insects and the piercing and suctorial 

 organs which it ensheaths, and gives besides a detailed account of 

 the associated musculature, chitinous framework, glands, &c. 



(a) The lahium is shown to be really double by its frequent terminal 

 splitting and slight ventral furrow. Herr Wedde maintains further, 

 that in this united organ, cardo, stipes, and palpi are really present. 

 The terminal joint is furnished not only with tasting rods, but with 

 a delicate umbrella-shaped organ which serves to surround the wound, 

 and to prevent the escape of the desired juice. The furrow of the labium 

 is, as is well known, roofed over by the labrum, the borders of which 

 are bent down, so that between the upper and lower lip a distinct tube 

 is formed. 



(6) The piercing and suctorial organs lie between the two, and 

 consist of a pair of clear, hollow, terminally toothed mandibles, and 

 within these two, very closely united, but anatomically and physio- 

 logically distinct, dark brown, hollow, terminally toothed maxillae, of 

 which the upper is in continuous connection with the pharynx, and 

 serves exclusively for the entrance of the nutritive juice, while the lower 

 is the exit canal of the salivary glands, from which there issues a 

 strongly alkaline fluid, stimulating the flow of food from the wound. 



(c) The musculature consists mainly (1) of the levatores and depres- 

 sor es labii, which also affect the dependent movement of the labrum ; 

 (2) of longitudinal muscles running along the joints of the labium 

 and effecting horizontal and vertical movements ; (3) of muscles 

 running across from the inner side of the labial joints to the chitinous 

 lining of the furrow, and probably narrowing the latter ; (4) of the 

 important retractors and protractors of the maxillae and mandibles ; 

 (5) of four dilators of the pharynx, which widen the cavity and produce 

 that alteration of pressure which in great part causes the upward flow 

 of the food-fluid ; (6) the complex muscles of a force-pump arrange- 

 ment to be afterwards noted. He describes in detail the structure and 

 functions of the chitinous framework associated with the pharynx. 



{d) The force-pump, first discovered by Landois, is a chitinous 

 structure lying below the widest portion of the pharynx. Provided 

 with valves, piston, and powerful muscles, it has, however, no con- 

 nection with the pharynx nor the suctorial act, but effects exclusively 

 the flow of the salivary fluid through the lower maxillary tube to 

 the exterior. It is characteristic of all the orders of Ehynchota with 

 piercing organs and suctorial tube, which Herr Wedde would dis- 

 tinguish as K. setifera, from the lower Pediculidae and Mallophaga, 

 which have neither piercing organs nor force-pump, and which he 

 * Arch. f. Naturgesch., li. (1885) pp. 113-43 (2 pis.). 



