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 tlie dorsal vessel, and passes straight back to be inserted into the 

 fore part of the follo^ving segment (foui-th abdominal). This muscle is identical with 

 that marked A by Lyonet. 



No. 2 (B of Lyouct) 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 into 

 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 inserted in front, immediately under and 

 behmd 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 whoUy straight 

 in its direction, but inclines a little downward iu 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 Ues 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 (E 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 parallel 

 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 aU the longitudinal muscles in the upper haK of the segment, and 

 shall now pass to those in the lower half. 



No. 16 ((/ of Lyonet) rises on the same transverse line as 4 and 5, and consequently 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 the third abdo- 

 minal segment. 



