. Smithsonian miscellaneous collections. tive maxillae alone have a musculature capable of giving them anindependent back-and-forth movement on the head. The biting pro-cedure of the mosquito, as deduced by Robinson (1939) from directobservation and a study of the mechanism of the feeding apparatus,is essentially as follows: A puncture of the skin is first effected bya thrust of the head transmitted to the bundle of stylets held inthe labial groove. The maxillary blades are then alternately by their 46 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. IO4 own muscles driven deeper into t
. Smithsonian miscellaneous collections. tive maxillae alone have a musculature capable of giving them anindependent back-and-forth movement on the head. The biting pro-cedure of the mosquito, as deduced by Robinson (1939) from directobservation and a study of the mechanism of the feeding apparatus,is essentially as follows: A puncture of the skin is first effected bya thrust of the head transmitted to the bundle of stylets held inthe labial groove. The maxillary blades are then alternately by their 46 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. IO4 own muscles driven deeper into the wound, each blade holding bymeans of its recurved teeth against the reverse pull of the retractors,which draw the head down and thus stretch the protractors of theopposite stylet. By repeated alternating action of the maxillae, eachblade successively overreaching the other, the whole bundle of styletsis drawn into the wound. As the stylets sink into the skin, the labium,holding the fascicle between the labella, bends backward beneath. Fig. 18.—Aedes aegypti (L.) feeding in the web of a frogs foot. (Redrawnfrom Gordon and Lumsden, 1939, with addition of neck sclerite.) At left, actively flexible end of stylet fascicle curved as it probes the tissueof the web. At right, the fascicle penetrated into a capillary. the head (fig. 18). The bending of the labium, which appears tobe a passive result of the lowering of the head, is believed by Rob-inson, and also by Gordon and Lumsden (1939) to be effected bymuscles attached on its base. The adhesion of the stylets when thefascicle is freed from the labium is attributed by Robinson to thepresence of a viscous liquid that bathes the stylets in the labialgutter. The action of the stylets within the tissue of the victim has beenstudied by Gordon and Lumsden (1939) by allowing mosquitoesto bite the thin web of a frogs foot, the latter being so arranged thatthe course of the stylets in the transparent web could be observedunder a microsc
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Keywords: ., bookauthorsm, bookcentury1800, bookdecade1860, booksubjectscience
