I 



NO. 3 INSECT HEAD SNODGRASS I47 



inflections of the stomodeal wall, continuous from the pharynx into 

 the oesophagus. In Lycophotia margaritosa each of these folds ends 

 at the opening of the crop in a prominent fleshy papilla covered with 

 small chitinous points. Between the folds are four deep channels ex- 

 tending from the mouth to the crop, two dorso-lateral, and two latero- 

 ventral. Possibly it is through these channels that the alimentary 

 liquid, which caterpillars frequently eject from the mouth when 

 irritated, is conveyed forward from the crop. 



The muscles of the crop (fig. 55, Cr) are arranged longitudinally 

 and circularly. The circular muscles (/), except for a few closely 

 placed anterior bands (k), are widely spaced, external circular fibers. 

 They all completely surround the crop like the hoops of a barrel. At 

 the junction of the crop with the oesophagus, there are several short 

 transverse fibers (/) confined to the dorsal surface. All the muscles 

 of the crop are strongly fibrillated (fig. 56 A, B, C, D). The circular 

 bands have distinct nuclei, but nuclei were not observed in the longi- 

 tudinal muscles of noctuid species examined. 



The longitudinal muscles of the crop (fig. 55, vi) have their origin 

 in single fibrillae (fig. 56 A) or small bundles of fibrillae (B) given 

 off from the posterior margins of the circular fibers. They are, there- 

 fore, of the nature of branches of the circular fibers, and this fact 

 may account for their lack of nuclei. Moreover, the longitudinal 

 muscles are not continuous, individual bands, but are everywhere 

 branched and intimately united by intercrossing bundles of fibrillae in 

 such a manner that the entire layer becomes a plexus of muscle tissue 

 (fig. 56 C) . Most of the fibrillae of this layer spring from the anterior 

 circular fibers, but probably all the circular fibers contribute at least 

 a few elements to the longitudinal plexus. On the anterior end of the 

 crop, the longitudinal fibrillae appear as simple connectives between 

 the transverse fibers (fig. 55, /). On the posterior end of the crop 

 (fig. 56 F), the longitudinal muscles again break up into smaller fibril 

 bundles, and at last into fine strands that reunite with the external 

 circular fibers of the crop or the proventriculus. 



The proventricular region (fig. 56 F, Pvcnt) resembles the oesoph- 

 agus in being surrounded by a close series of strong circular muscle 

 fibers (w). There is no distinct inner muscular sheath here, but the 

 circular fibers are all connected by small bundles of fibrillae going from 

 one to another (G), some to the first neighboring fibers, others to 

 the second, third, or fourth removed in either direction. The proven- 

 triculus has a special feature in the presence of an external layer of 

 fine, widely-spaced, longitudinal muscles, stretched freely between its 

 two ends (fig. 56 F, o). These threadlike strands arise anteriorly 



