MOSQUITOES 



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compound eyes is called the frons, in front, and the occiput posteriorly. 

 The nape is back of the occiput. The bulbous prolongation of the frons which 

 projects over the attachment of the proboscis is the clypeus. The clypeus is hairy 

 in the Culex; scaly in Stegomyia. The proboscis is straight in all mosquitoes of 

 importance medically. It consists of a fleshy, scaled, gutter-shaped portion be- 

 neath, known as the labium, which terminates in two hinge-joint processes the 

 labella. At the end of the labium is a thin membrane (Button's membrane). It 

 is through this that filarial embryos are supposed to pass on their way from the 

 interior of the labium to enter the person bitten. The labium may be considered 

 as the sheath of a knife, holding and protecting the slender, blade-like penetrating 



FIG. 89. Anatomy of mosquito, i, Dorsal view of mosquito; 2, wing of mos- 

 quito; A, costal vein; B, mid cross vein; C, posterior cross vein; D, first fork-cell; 

 E, second fork-cell; 3, various types of scales; a, flat head scales; b and c, Mansonia 

 wing scales; d, upright forked head scales; e, f, g and h, various shapes of thoracic 

 scales. 



organs. Lying in this groove we have, from above downward, the horseshoe- 

 shaped labrum epipharynx, the under surface of which is open. This when closed 

 by the underlying hypopharynx forms a tube through which the blood is sucked 

 up by the mosquito. In the hypopharynx, which somewhat resembles a hypoder- 

 mic needle, is a channel, the veneno-salivary duct. It is down this channel that 

 the malarial sporozoite passes. There are two pairs of mandibles and two pairs 

 of maxillae on either side of the hypopharynx the mandibles above and the maxillae 

 below. The serrations of the maxillae are coarser than those of the mandibles. 

 The sensory organs, the palps, lie on either side of and slightly above the proboscis. 



