. Smithsonian miscellaneous collections. and has anelongate form (E). From its anterior end the thick beak curves down-ward and backward when not in use, with its tip lodged in a grooveof the presternum. The mandibular and maxillary stylets arise farback in the head behind the compound eyes (E, only the maxillarystylet shown) ; their protractor muscles (41), therefore, are unusuallylong. In the flexed position of the beak the stylets follow the anteriorcurvature of the labium as they issue from the head, and their tipslie in the labial groove at the apex of the terminal segment. Thelabium has
. Smithsonian miscellaneous collections. and has anelongate form (E). From its anterior end the thick beak curves down-ward and backward when not in use, with its tip lodged in a grooveof the presternum. The mandibular and maxillary stylets arise farback in the head behind the compound eyes (E, only the maxillarystylet shown) ; their protractor muscles (41), therefore, are unusuallylong. In the flexed position of the beak the stylets follow the anteriorcurvature of the labium as they issue from the head, and their tipslie in the labial groove at the apex of the terminal segment. Thelabium has little flexibility at its joints and is not capable of making anelbow bend as in the bed bug and many other Heteroptera, but itis freely hinged to the head by its thick base, and is provided withstrong muscles by which it can be turned vertically or directedanteriorly (E). When the beak swings forward the anterior side ofthe labial base folds into the head; the distance from the head to the no. 7 BITING AND SUCKING INSECTS SNODGRASS 105. Fig. 39.—Assassin bugs, family Reduviidae, and a bloodsucker of the familyLygaeidae. Order Hemiptera. (A, B, C, D, one-third larger than natural size.) A, Reduvius pcrsonatus (L.), a common, painfully biting assassin bug ofEurope and North America. B, Triatoma infestans (Klug), a South Americanvector of Chagas disease. C, the wheel bug, Arilus cristatus (L.). D, Cleradaapicicomis Sign., a South American blood-feeding member of the , head of Reduvius pcrsonatus, showing beak in positions of flexion and exten-sion, and automatic protraction of stylets. F, section of head of same, showingsucking pump and salivary ejection pump (simplified from Weber, 1930). Aclp, anteclypeus; CbP, cibarial pump; Clp, clypeus; E, compound eye; Lm,labrum; MxL, maxillary lobe; MxS, maxillary stylet; O, ocellus; Oe, oesoph-agus ; SIDct, salivary duct; SIO, salivary orifice; SIP, salivary pump; Stl,fascicle of stylets. Muscles.—5a, 5b, 5c, dilators of ci
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Keywords: ., bookauthorsm, bookcentury1800, bookdecade1860, booksubjectscience
