66 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82 



106. Posterior levator of the tibia (fig. 37 C, E). — A long, pinnate 

 muscle with fibers arising on almost entire length of dorso-posterior 

 wall of femur ; inserted by strap-like tendon on dorsal angle of base of 

 tibia (E, 106). 



107. Depressor of the tibia (fig. 36 B, C). — The largest muscle in 

 the middle femur, comprising three groups of fibers, all inserted on a 

 long apodeme arising from small plate in ventral membrane of knee 

 joint. Principal group of fibers (B, loya) forms a long pinnate mus- 

 cle arising ventrally in proximal part of femur ; second group a small 

 bundle of fibers (lo/b) arising in base of trochanter and joining with 

 those of first group; fibers of third group (loyc) arise anteriorly and 

 dorsally in distal two-thirds of femur and converge ventrally to inser- 

 tion on base of depressor apodeme. 



108. Levator of the tarsus (fig. 42 A). — Origin dorsally in distal 

 third of tibia ; insertion on dorsal lip of base of tarsus. 



log. Depressor of the tarsus (fig. 42 A). — Origin ventrally in dis- 

 tal three- fourths of tibia ; insertion on ventral lip of base of tarsus. 



no. Depressor of the pretarsus: retractor of the clazvs (figs. 36 C, 

 42 A, C) . — Fibers arising in femur and tibia ; inserted on long, thread- 

 like apodeme arising from unguitractor plate at base of claws (fig. 

 42 C, iioAp) and extending through tarsus (A) and tibia, and into 

 femur. Principal group of fibers a long, tapering bundle (fig. 36 C, 

 no) arising proximally on posterior wall of femur and inserted on 

 end of tendon ; two smaller groups of fibers in upper end of tibia, one 

 arising anteriorly in base of tibia, the other dorsally, both inserted on 

 tendon just above middle of tibia. 



Since the second thoracic spiracle lies within the region of the meso- 

 thorax, its muscle belongs to the same segment. 



111. Closing muscle of the second spiracle (fig. 52 B). — Origin on 

 small lobe (o) of posterior dorsal margin of mesocoxal cavity; inser- 

 tion on ventral lobe of spiracular lips («)• 



THE METATHORACIC MUSCLES 



The musculature of the metathorax almost duplicates that of the 

 mesothorax, with the principal difference that there are no oblique 

 dorsal muscles and that there is only one pair of tergo-sternals in the 

 metathorax. 



112. Longitudinal dorsal muscles (fig. 34). — Most of the fibers 

 extend between middle phragma and third phragma (jPh), though a 

 few dorsal ones are attached posteriorly on the postnotal plate (PNz)- 



