NO. 8 ANATOMICAL LIFE OF THE MOSQUITO — SNODGRASS 



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articular point (fig. 5 E,F, a) that articulates with a process of the 

 hypostomal margin just laterad of the base of the maxilla (fig. 7 B, a). 

 Its anterior articulation (fig. 5 D, c) is with the hypopharyngeal bar 

 (fig. 7 B, hb). The mandibles move in the transverse plane by strong 

 abductor and adductor muscles. The principal function of mandibles 

 of this type is the collection by their setal combs of food particles from 



Fig. 5. — Larval mandibles. 



A, Tipula abdominalis, right, ventral. B, Lutsia sp., right, ventral. C, Toxo- 

 rhynchites rutilus, left, dorsal. D, Anopheles quadrimaculatus, left, dorsal. E, 

 Culex, sp., right, ventral. F, Aedes aegypti, right, ventral. 



a, posterior (ventral) articulation; c, anterior (dorsal) articulation. 



the labral brushes, but the incisor points are said to break up larger 

 particles that collect on the hypopharynx. 



The mandibles of predaceous larvae, such as Culex vorax (fig. 5 B) 

 and Toxorhynchites (C), are strongly toothed jaws, the points of 

 which come together in adduction (fig. 4 E). Most larval Nematocera 

 have jawlike mandibles (fig. 5 A), though they present many varieties 

 of structure. C. vorax is a culicine mosquito, and its mandible (B) 

 might be derived from the culicine type, but the mandible of Toxo- 

 rhynchites (C) is a typical biting insect jaw. 



The maxillae. — The maxillae of the mosquito larva (fig. 6 B-F) are 

 so greatly simplified that they have lost the appearance and structure 

 of an ordinary insect maxilla. They are borne on the transverse 

 hypostomal margins of the postgenae at the sides of the hypostomium, 



