Puate LX 
THE HOG LOUSE, HAEMATOPINUS SUIS LINNE ~ 
1, Transverse section through anterior region of head just posterior to section shown in Plate LXI, 1 
(a, buccal plate; b, dorsal element of piercers; e, anterior ends of pumping pharyngeal tube; 1, structures 
corresponding to ‘‘ mandibles’ of Sikora; mm, muscles of these; nn, dorsal protractors of buccal plate; 
o, prefrontal ganglion); 2, dorsal aspect of anterior part of stomodaeum (a, buccal plate; e, pumping 
pharyngeal tube; g, pumping pharynx; k, pharynx; nn, dorsal protractor muscles; pp, ventral protractor 
muscles; qq, anterior dorsal retractor muscles; rr, posterior dorsal retractor muscles; ss, dorsal muscles of 
pharynx; t, esophagus; uu, ‘“ mandibles”’ of Enderlein; vv, lateral tendon muscles; w, haustellum with 
buccal teeth; dilator muscles of pumping pharynx not shown); 3, ventral aspect of anterior part of 
stomodaeum (xx, ventral retractor muscles; other lettering as in 2); 4, ventral aspect of haustellum pro- 
truded and showing buccal teeth; 5, transverse section through anterior region of thorax, showing posterior 
ends of rami of piercers with their muscle attachments (a, cuticula enclosing piercers and esophagus; b, 
dorsal element of piercers; d, ventral element of piercers; ee, occipital apodeme; i, aorta; k, recurrent 
nerve; ll, tracheae; m, connectives; nn, posterior arms of apodemes of prothorax and prosternum; 0, salivary 
gland between rami of piercers; t, esophagus); 6, mouth parts (b, dorsal element of piercers; c, salivary 
duct; dd, rami of ventral element of piercers; 0, salivary gland between rami of piercers; p, anterior end of 
chitinous plate imbedded in floor of sheath; ee, protractor muscles of sheath and piercers; ll, ventral lateral 
retractors of sheath and piercers; mm, dorsal lateral retractors of sheath and piercers; nn, posterior 
retractors of sheath and piercers; posterior retractors inserted in end of each ramus not shown; sheath torn 
away leaving only ventral plate and piercers, so that lateral retractor muscles appear in approximate 
position); 7, dorsal element of piercers (a, bulb at end of salivary duct; salivary duct underlying piercer 
shown as a dotted line in proximal part only); 8, ventral element of piercers (p, chitinous plate imbedded 
in floor of sheath); 9, anterior ends of ventral elements of piercers 
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