. Smithsonian miscellaneous collections. y Stephens and Newstead (1907) toeffect a rotation of the theca, thus enabling the labellar teeth toexert a cutting action on the skin. Another pair of larger musclesin the bulb of the theca (F) have long tendons that traverse thelabium to be attached on the labella, and these muscles effect directlya retraction of the labellar plates. Protraction of the theca reversesthe movement and introverts the labellar teeth. While it wouldappear that the appressed labella in the protracted position are them-selves sufficiently rigid to serve as a penetrating poin
. Smithsonian miscellaneous collections. y Stephens and Newstead (1907) toeffect a rotation of the theca, thus enabling the labellar teeth toexert a cutting action on the skin. Another pair of larger musclesin the bulb of the theca (F) have long tendons that traverse thelabium to be attached on the labella, and these muscles effect directlya retraction of the labellar plates. Protraction of the theca reversesthe movement and introverts the labellar teeth. While it wouldappear that the appressed labella in the protracted position are them-selves sufficiently rigid to serve as a penetrating point for the probos-cis, it is generally said that the everted teeth are the effective cuttingagents that puncture the skin, the proboscis being then sunken intothe flesh. Movements of the proboscis in the wound probably causea laceration that increases the blood flow. The sucking apparatus of Glossina has the typical muscoid struc-ture. The cibarial pump (termed the pharynx by Jobling, 1933) no. 7 BITING AND SUCKING INSECTS—SNODGRASS 75. Fig. 29.—Tsetse fly, Glossina, horn fly, Siphona, and stable fly, Stomoxys, headand feeding apparatus. Order Diptera, families Glossinidae and Muscidae. A, Glossina pal pal is , male (length 11 mm.). B, same, head and pro-boscis. C, Siphona irrita7is (L.), proboscis. D, Stomoxys calcitrans (L.),proboscis. E, Glossina palpalis, proboscis and sucking pump, stylets separatedfrom labium. F, same, vertical section of head and base of proboscis (simpli-fied from Jobling, 1933). G, Glossina fusca (Walker1), cross section of pro-boscis (from Vogel, 1921). H, Glossina palpalis, horizontal section of distalend of labium (simplified from Jobling, 1933). Ant, antenna; b, bulb of labium; Br, brain; CbP, cibarial pump; dp, clypeus;fc, food canal; Hphy, hypopharynx; Hstl, haustellum; Lbl, labellum; Lm,labrum; LG, labial gutter; MxPlp, maxillary palpus; Oe, oesophagus; Prb,proboscis; Ptl, invaginated ptilinum; Rst, rostrum; sc, salivary canal; SIP,saliv
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Keywords: ., bookauthorsm, bookcentury1800, bookdecade1860, booksubjectscience
