NO. 6 



CATERPILLAR AND BUTTERFLY — SNODGRASS 



21 



Fig. io (See opposite page). — Somatic muscles of the salt marsh caterpillar, 



Estigmene acraea. 



A, External muscles of right half of third abdominal segment as seen after 

 removal of longitudinal bands, showing basal muscles of proleg. B, Right half 

 of fourth abdominal segment, ventral longitudinal muscles partly removed. C, 

 Ventral half of fourth abdominal segment. 



Fig. ii (above). — Somatic muscles of the tent caterpillar, 

 Malacosoma americanum. 



A, Ventral prothoracic muscles of head. B, Dorsal muscles of back of head. 

 C, Right half of prothorax and head muscles. D, Same after removal of head 

 muscles. E, External ventral and right lateral muscles of metathorax. F, Ven- 

 tral and right external muscles of mesothorax and metathorax. 



