I02 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I03 



and postmentum. {Protractor labii Morison ; posterior labial adductor 

 Duncan.) 



ig. Premental retractor of the ligula (fig. 7 A). — Arises laterally 

 in base of prementum, tapers to tendinous insertion on ligular arm 

 {h) of prementum just laterad of ly. This muscle is probably the 

 paraglossal muscle of the labium ; functionally it is accessory to ly 

 in retraction of the ligula. {Retractor linguae brevis Wolflf ; anterior 

 flexor of the ligula Duncan ; wrongly described by Morison as flexor 

 palpi maxillaris. ) 



20. Flexor of the glossa, retractor of the tongue (fig. 7 A, B). — 

 Origin posteriorly in base of prementum, insertion by long tendon 

 close to side of base of glossal rod. The muscles of this pair serve 

 to shorten the tongue or to roll it from side to side. (Smaller branch 

 of retractor linguae biceps Wolff ; retractor, ligulae inferior Morison ; 

 posterior flexor of the ligula Duncan.) 



21. Flexor of the labial palpus (fig. 8 A). — A flat pinniform muscle 

 arising on side of prementum, inserted by long tendon on rod in 

 posterior wall of palpiger. It depresses the palpus and folds the latter 

 back behind the stipes. {Extensor palpi maxillaris Morison ; depressor 

 of the labial palpus Duncan. Morison mistakenly assigns two muscles 

 to the labial palpus in the bee. Duncan finds but one in Vespula.) 



22. Muscle of the second segment of the labial palpus (fig. 8 A). — 

 Origin in base of first palpus segment, insertion on base of second 

 segment; flexes the second segment mesally, opposed by elasticity of 

 the joint. 



2^. Dilator of the salivary syringe (fig. 7 A, C). — A flat muscle 

 arising on anterior lateral margin of prementum, inserted medially on 

 anterior wall of salivary syringe. {Protractor liguae Wolff; dilator 

 ampidlae superior Morison; dilator of the salivarium Duncan.) 



24. Compressor of the salivary syringe (fig. 7 A, C). — Largest 

 muscle in prementum, arising proximally, inserted distally on lateral 

 margins of salivary syringe. Probably compresses the syringe by 

 lateral tension. (Principal branch of retractor linguae biceps Wolff; 

 dilator ampidlae salivae posterior Morison ; posterior muscle of 

 salivarium Duncan.) 



<?5. Retractor, or levator, of the epipharynx (fig. 10 C). — A group 

 of fibers arising on distal part of clypeus, diverging to insertions 

 within the epipharynx. {Levator, veli palatini Wolff.) 



26, 2"/, 28, 2g, JO. Dilators of the suctorium (fig. 10 C). — Five 

 large, paired bundles of short fibers arising on clypeus and inserted 

 on anterior wall of cibarial region of sucking pump. 



