86 ENTOMOLOGY 
The muscles of the trunk are segmentally arranged—most 
evidently so in the body of a larva or the abdomen of an 
imago, where the musculature is essentially the same in sev- 
eral successive segments. In the thoracic segments of an ima- 
go, however, the musculature is, at first sight, unlike that of 
Fic. 106. Fic. 107. Fic. 108. 
Muscles of cockroach; of ventral, dorsal and lateral walls, respectively. a, alary 
muscle; abc, abductor of coxa; adc, adductor of coxa; ef, extensor of femur; h, head 
muscles; /s, longitudinal sternal; /t, longitudinal tergal; Jth, lateral thoracic; os, 
oblique sternal; ot, oblique tergal; ts, tergo-sternal; ts, first tergo-sternal.—After 
Miatu and Denny. 
the abdomen, and in the head it 1s decidedly different; though 
future studies will doubtless show that the thoracic and cepha- 
lic kinds of musculature are only modifications of the simpler 
abdominal type—modifications brought about in relation to 
the needs of the legs, wings, mouth parts, antennze and other 
movable structures. 
The muscular system has been generally neglected by stu- 
dents of insect anatomy; the only comprehensive studies upon 
the subject being those of Straus-Durckheim (1828) on the 
beetle Melolontha; Lyonet (1762), Newport (1834) and 
Lubbock (1859) on caterpillars; and the more recent studies 
of Lubbock and Janet on Hymenoptera. 
