MINUTE STRUCTURE OF MUSCLES 



215 



these arises from the superior lateral border of the pronotum, the second from 

 the superior posterior border, the third from the sides of the prothorax, and the 

 fourth a little nearer posteriorly, and the whole of them are attached by narrow 

 tendons to the sides of the coxa. But there is only one extensor nmscle to this 

 part. In like manner, the extensor of the trochanter is formed of three portions 

 (Fig. 233, a, b, c) ; but there is only one flexor (d), and one abductor (e). In 

 the femur, there is one extensor (/), 

 a long penniform muscle that occupies 

 the. superior part of the thigh, and is 

 attached by a tendon to the anterior- 

 posterior margin of the joint formed by 

 the end of the tibia. There is also but 

 one flexor (y) in the femur, which, like 

 the preceding muscle, is penniform, and 

 occupies the inferior portion of the 

 femur, and its tendon is attached to the 

 inferior border of the tibia. In the tibia 

 itself there is also one flexor and one 

 extensor. The Jlc.ror (i) occupies the 

 superior portion of the limb, and ends in 

 a long tendon (I) that passes directly 

 through the joints of the tarsus, on their 

 inferior surface, and is attached to the 

 inferior margin of the claw (</). The 

 extensor (h) occupies the inferior portion 

 of the tibia, and is shorter than the pre- 

 ceding muscle, like which it ends in a 

 long tendon that is attached to the upper 

 margin of the claw. Besides these mus- 

 cles, which are common to the joints of 

 the tarsus, there are two others belonging 

 to the claw, situated in the last joint. 

 The first of these, the extensor (m), is 

 short, and occupies the superior portion 

 of the last phalanx of the tarsus, and the 

 other, the flexor (jt), is a much longer 

 penniform muscle, which occupies nearly 

 the whole of the upper and under surface 

 of the posterior part of the phalanx, and 

 is attached, like the long flexor of the 

 tarsus, to the inferior part of the claw." 



These are the muscles of the prothorax, 

 and its organs of locomotion. The reader 

 is referred for a further account of the muscles of the hinder thoracic and of 

 the abdominal segments to Straus-Durckheim's original work. 



Minute structure of the muscles. - - The muscular fibres of insects 

 are striated (Figs. 235-238), even those of the alimentary canal ; 

 the only notable exception being the alary muscles of the pericardial 

 septum, while Lowne states that certain of the thoracic muscles of 

 the blow-fly are not striated (Miall and Denny). 



In describing the minute structure of the muscles of ants, wasps, 



FIG. 233. Muscles of the fove leg: of 

 Jft/o/onifia vutr/urin : a. b. <, three divi- 

 sions of the extensor of the trochanter ; (f, 

 flexor, e, abductor, of the trochanter: /, 

 extensor of the femur; g. flexor of the fe- 

 mur; A, extensor of the tibia; /, flexor of 

 the tibia; I, tendon attached to the lower 

 edpre of the claw (g) ; in, extensor, .. flexor, 

 of the claw. After Strauzs-Durckheiui, from 

 Newport. 



