78 



TEXT-BOOK OF ENTOMOLOGY 



In the Diptera the hypopharynx reaches its highest development 

 as a large, stout, awl-like structure. 



Meinert, in his detailed and elaborately illustrated work, Trophi 

 Dipterorum (1881), has made an advance on our knowledge of the 



sm 



Ibr 



mx.p 



FIG. 81. Culex pipiens, section of head : oe, oesophagus; sm, upper muscle, lm, lower mus- 

 cle of the oesophagus ; ph, pharynx ; rm, retractor muscle of the receptacle (r) of the salivary duct 

 (s.d) ; Ibr, labrum ; ep, left style of the epipharynx ; /, part of front of head. After Meinert'. 



hypopharynx and its homologies, both by his evidently faithful de- 

 scriptions and dissections, and by his admirably clear figures. 



mph 



FIG. 82. Pharynx and 

 hypopharynx of Simuiium 

 funeipea : Iph, lower lamina 

 of th* pharynx ; p, the sali- 

 vary" duct (H.d) perforating 

 the pharynx ; o, orifice of 

 the duct; xhp, styles of the 

 hypopharynx ; /iiph, mem- 

 branous edge of the hypo- 

 pharynx ; m, protractor 

 muscle of the pharynx ; 

 gp, gustatory papillae. 

 After Meinert. 



" The hypopharyux, a continuation of the lower 

 edge (lamina) of the pharynx, most generally free, 

 more or less produced, acute anteriorly, forms with 

 the labrum the tube of the pump (antliw}. (The hypo- 

 pharynx when obsolete, or coalesced with the canal of 

 the proboscis, is the theca ; in such a case the siphon 

 or tube is formed by the theca and labrum.) Mean- 

 while the hypopharynx, the largest of all the trophi 

 (omnium trophorum maximus), constitutes the chief 

 piercing organ (telum} of Diptera. The hypopharynx 

 is moved by protractor, most generally quite or very 

 powerful, and by retractor muscles. 



" The efferent duct of the thoracic salivary glands 

 (ductus salivalis) perforates the hypopharynx, more 

 or less near the base, that the saliva may be ejected 

 through the canal into the wound, or that it may be 

 conducted along the labella. Very rarely the salivary 

 duct, perforating the hypopharynx, is continued in 

 the shape of a free, very slender tube. 



"The salivary duct behind the base of the hypo- 

 pharynx forms the receptacle or receptaculum, provided 

 with retractor and levator muscles." 



It has been carefully studied by Meinert in 

 a species of Culex (Fig. 81), Simulimn (Fig. 

 82), Tabanus (Fig. 83), and in Asilus (Fig. 84), 



