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SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I43 



Th 



Ab 



Hprry "Spn J? 



Fig. 5. — External features of a caterpillar. 



A, Typical structure of a caterpillar. B, Head of a silkworm, lateral. C, Same, 

 ventral. D, A thoracic leg. E, Longitudinal section of a caterpillar's head, 

 diagrammatic, showing united hypopharynx and labium enclosing the silk press 

 (salivarium). F, Left mandible and muscles of a tomato worm, anterior. 



Ab, abdomen; ab, abductor muscle; ad, adductor muscle; Ant, antenna; H, 

 head; Hphy, hypopharynx; L, thoracic leg; Lb, labium; Lm, labrum; Md, 

 mandible ; Mx, maxilla ; PrL, prolegs ; Sp, spiracle ; Spn, spinneret ; Th, thorax. 



