174 MR. LUBBOCK ON THE CUTANEOUS MUSCLES 
No. 1 is a broad and strong muscle which is inserted into the skin near the front of the 
segment on one side of the dorsal vessel, and passes straight back to be inserted into the 
fore part of the following segment (fourth abdominal). This musele is identical with 
that marked A by Lyonet. 
No. 2 (B of Lyonet) is in fact treble, and consists of three muscles joined end to end; 
posteriorly it is inserted at the ventral side of the preceding, and passes forward parallel 
to it; but instead of being attached at the fore part of the third abdominal segment, it 
unites with the corresponding muscles of the two preceding muscles, and is inserted. Hr 
the fore part of the first abdominal segment. 
No. 3 is absent from this segment. 
No. 4 (D of Lyonet) lies under No. 1, and is T in front, immediately under and 
behind it; posteriorly, however, it does not pass quite so far back, but is inserted at the 
line of separation of the third and fourth abdominal segments. It is not wholly straight 
in its direction, but inclines a little downward in front. 
No. 5 (G of Lyonet) lies under the preceding, and is in some respects opposite to it; 
that is to say, the anterior insertion is on the dorsal side, and the posterior on the ventral, 
but on the same transverse lines. 
These first five muscles must tend to contract the skin of the back. 
No. 6 (E of Lyonet). This muscle lies at the ventral side of 2, and just at the dorsal 
side of the great lateral trachea. Its attachments are hidden by the transverse muscle 
35, which will presently be described, and are on the same transverse lines as those of 
No. 1. 
No. 7 (H of Lyonet) This muscle rises on the ventral side of No. 6 and on the same 
transverse line as the posterior insertions of Nos. 4 and 5, and passing forward and upward 
under Nos. 6 and 8, is attached on the dorsal side and near the anterior end of No. 6; this 
muscle and the next following bear the same relation to No. 6 that Nos. 4 and 5 do 
to No. 1. 
No. 8 (F of Lyonet) rises posteriorly between 5 and 6, and passing forward and down- 
ward between 6 and 7, is inserted at the ventral side of the anterior end of 6. 
No. 9 (I of Lyonet). This muscle is a little more than half as long as 5 and puede 
to it, lying on the dorsal side of the posterior half. 
Nos. 10 and 11 (L of Lyonet) are attached between the posterior insertions of 1 and 6, 
one on each side of the posterior end of 8, and pass straight forward for two-thirds of the 
length of the segment. 
Nos. 12 to 15 (Q of Lyonet) rise almost on the same transverse line and underneath 4, 
and pass forward and downward, so as to cross under 9 and 5, for one-third of the length 
of the segment. 
I have thus described all the longitudinal muscles in the upper half of the segment, and . 
shall now pass to those in the lower half. 
No. 16 (d of Lyonet) rises on the same transverse line as 4 and 5, and "—— on 
the line of division between the third and fourth abdominal segment, on the ventral side 
of the great lateral trachea, and passes straight forward to the front of - _ abdo- 
minal segment. 
