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TEXT-BOOK OF ENTOMOLOGY 



of Cossus, which are voluminous, were regarded by Lyonet as 

 caisseaux dissolvans." Dr. Auzoux (1849), in his celebrated model 



FIG. 323. Left side of the head of the silkworm: a, adductor muscle of the mandible, from 

 which the muscular fibres have been removed ; l>, upper fibres of the same : c, lower fibres cut 

 away to show the adductor muscle (e) ; d, fibres inserted on the accessory adductor lamella ; /, 

 (esophagus, much swollen ; g. salivary gland ; A, dorsal vessel ; i, I, tracheae of the mandibular mus- 

 cles ; k, trachea; , optic nerve. After Blanc. 



of the silkworm, represented them accurately, while Cornalia briefly 

 described them as opening into the mouth. The first satisfactory 



description is that of Blanc 

 (1891), who states that in the 

 silkworm "the two salivary 

 glands " are small, flexuous, 

 yellow tubes, which occupy a 

 variable position on the sides 

 of the oesophagus (Fig. 323). 

 The glandular portion passes 

 into the head, ending at the 

 level of the adductor plate of 

 the mandibles (Fig. 324, 3), 

 and entering the buccal cavity 

 at the base of the mandible, 

 as seen in Fig. 323. It is 

 plain, when we recognize the 

 direct homology of the silk- 

 glands of the caterpillars with 

 the salivary glands of other 

 insects, and of the spinneret 

 with the hypopharynx, that 



B 



of the silkworm 



l jra 



Fi<;. 324. Lower side of the head 

 exposed, the spinning apparatus, the ce 

 lion. iind the adductor of the left mandible removed : 

 M, mandible ; /', abductor of the mandible ; R, ad- 

 ductor; X, salivary yland attached at. 1 to the ('dye of 

 the adductor muscle; <>. n, transverse portion of the 

 "liyuid"; ">, masticator nerve and its recurrent 

 branch (7) ; L, tongue cut horizontally. After Blanc. 



