1192 
Journal of Agricultural Research 
Vol. XXVIII, No. 12 
MUSCLES OF THE TRUNK 
The muscles of the trunk have a strictly metameric arrangement and conform 
more or less closely to a definite and typical arrangement in all segments. The 
arrangement of the muscles in the thorax differs slightly from that of the ab¬ 
dominal muscles. In the abdomen the same arrangement of muscles prevails 
in all the segments with the exception of the 10th. In the 10th segment the 
muscles characteristic of the other segments are almost entirely wanting, the only 
Fig. 4—A, inner surface of right half of body wall of thoracic segments, showing musculature, X 10; B, 
inner surface of right half of body wall of fourth and fifth abdominal segments, showing musculature, 
X 10 
trunk muscles present being a few fibers running from the lateral border of the 
anus to the anterior (lateral) borders of the segment. 
The trunk muscles, taking the 4th and 5th abdominal segments (fig. 4, B) as 
typical, are the ventral longitudinal, ventral oblique, lateral oblique, dorso- 
ventral, dorsal longitudinal, and dorsal oblique. 
VENTRAL LONGITUDINAL MUSCLES 
These muscles (fig. 4, B, VLMcl) are not, strictly speaking, longitudinal, since 
they diverge slightly from the long axis of the larva in a cephalo-laterad direction. 
