OF THE LARVA OF PYG^RA BUCEPHALA. 175 



Nos. 17 and 18 (c and b of Lyonet) are parallel, similar to, and on the ventral side of 16. 



Nos. 19 and 20 (Jf and e of Lyonet) arise under the posterior ends of 16 and 17, and are 

 inserted in front under the anterior ends of 17 and 18. They are therefore not quite 

 parallel to the axis of tlie body, but pass a little downward in their course forward, and 

 are moreover nearer together in front. They appear to correspond to the two muscles 

 marked ff and e by Lyonet ; these two, however, are not parallel to and at the side of 

 one another, but the latter overlaps the former in front. 



No. 21 (a of Lyonet) is parallel to 16, 17 and 18, but is altogether rather further back, 

 so that its attachments in some respect alternate with those of 16, 17 and 18, though they 

 are not nearly midway. 



No. 22 {i of Lyonet) lies under the preceding muscle, but inclines to the median line 

 behind. It is generally bifid in front. 



No. 23 (/ of Lyonet) rises on the dorsal side of 24 and runs parallel with it, to be in- 

 serted under the fore end of 16. 



No. 24 (part of g of Lyonet) rises just in front of the ganglion and on the same trans- 

 verse line as 21, and passing forward and upward joins 23, and is inserted vnXh it under 

 the fore end of 17. 



No. 25 (part of g of Lyonet) rises near the middle line of the body, and passing dia- 

 gonally forward and upward joins 24, and is inserted with it under the fore end of 17. 



No. 26 {h of Lyonet) rises on the same transverse line as 56 and 17, close to the dorsal 

 side of the posterior end of 28, and under 25, and passes forward and upward parallel to 

 that muscle, to be inserted under its anterior attachment. 



No. 27 (part of k of Lyonet) is wanting in this segment. 



No. 28 (part of k of Lyonet) rises on the ventral side of the hind end of 19, and passing 

 forward and downward towards the ganglion is attached to a ridge, which commences 

 near the middle line of the posterior end of the segment and is continued forward, at the 

 same time curving uj^ward. It is broadest in front, where also it is often divided into 

 several heads. 



Nos. 29 and 30 {p of Lyonet) . These two muscles lie on the ventral side of, and parallel 

 to, the preceding. These three muscles vary considerably in form and relative size. 



No. 31 (part of t of Lyonet) rises under the posterior end of 18, and passing forward 

 and upward at about one-third of the segment at an angle of 50°, is very much hidden by 

 the fold of skin forming the boundary of the two segments. 



No. 32 (part of I of Lyonet) lies parallel to, and on the dorsal side of, the preceding. 



Nos. 33 and 34 (part of I of Lyonet) lie parallel to, and on the dorsal side . of, the 

 preceding. 



I have now completed the description of the longitudinal muscles and come therefore 

 to that of the transverse series. 



The first two of this series pass over or rather Laside the great lateral trachea and 

 the muscle 6; the other transverse muscles lie between the longitudinal series and 

 the skin. 



No. 35 (part of B of Lyonet), arising in part opposite and on the dorsal side of 16 of this 

 segment, and partly opposite the hind part of the corresponding muscle of the preceding 



