OF THE LARVA OF PYGÆRA BUCEPHALA. 175 
Nos. 17 and 18 (c and of Lyonet) are parallel, similar to, and on the ventral side of 16. 
"Nos. 19 and 20 (ff 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 the 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 f 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 (f 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 with 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 (4 of Lyonet) rises on the same transverse line as 56 and 17, close to the dorsal 
side of the posterior end of 23, 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 upward. 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 % 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. Å 
No. 32 (part of £ of Lyonet) lies parallel to, and on the dorsal side of, the preceding. 
Nos. 33 and 34 (part of ¢ of Lyonet) lie parallel to, and on the dorsal side of, the 
preceding. 
I have now completed the description of the longitu 
to that of the transverse series. 
The first two of this series pass over or 
the muscle 6; the other transverse muscles lie 
the skin, 
rt i i 6 of this 
No, 35 ising i osite and on the dorsal side of 1 
(part of 8 of Lyonet), arising in part opp 5 DU Ue pecelíng 
segment, and partly opposite the hind part of the correspon 
dinal muscles and come therefore 
rather inside the great lateral trachea and 
between the longitudinal series and 
