Prats LIX 
THE HOG LOUSE, HAEMATOPINUS SUIS LINNE 
1, Diagrammatic representation of primary and secondary tracheae; 2, stigma, vestibule, bulla, and 
trachea, drawn from cleared specimen; 3, section through abdominal stigma (a, vestibule; b, lever; c, bulla; 
d, intrinsic muscle; e, extrinsic muscle); 4, ventral abdominal muscle plate of female, ventral aspect; 5, 
right lateral abdominal muscles of segment 4 of male (drawn from gross dissection); 6, heart and one-half 
of length of aorta (a, pericardial cells); 7, transverse section through heart in region of ostium; 8, central 
nervous system and anterior part of sympathetic system (a,frontal ganglion; b, recurrent nerve; ¢, brain; 
d, subesophageal ganglion; e, connectives; f, prothoracic ganglion; g, mesothoracic ganglion; h, metathoracic — 
ganglion and abdominal ganglion; i, visceral nerves); 9, sections through tip of euaiseioe: showing multi- 
nuclear sensory cells (drawn with oil immersion) 
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