106 ILLINOIS BIOLOGICAL MONOGRAPHS [226 



EXPLANATION OF PLATE 



Gordius robuslus 

 Fig. 115. — Nerve fibre entering hypoderm of adult; X 475. 



Fig. 116. — Early stage in development of fibrous cuticula; slightly later stage than Fig. 35; 

 X 800. 



Fig. 117. — Fibrous cuticula about half developed; X 430, 



Fig. 118. — Adult; nerve fibres passing from neural lamella into hypoderm; X 450. 



Fig. 119. — Fibrous cuticula; development almost complete; X 625. 



Fig. 120. — Nerve fibres in hypoderm of adult; X 435. 



Fig. 121. — Cross section thru inner, ventral waU of prong of male; shows stout bristle; X 625. 



Fig. 122.— Section slightly outward from that of Fig. 121; X 625. 



Fig. 123. — Section thru outer wall of prong of same specimen; X 625. 



Fig. 124. — Old specimen; section showing extreme degeneration of muscles; X 430. 



Fig. 125. — Section thru old specimen; shows beginning of degeneration of muscle fibres; X 430. 



Fig. 126. — End of muscle cell of adult; isolated after maceration with nitric acid; X 625. 



