84 ILUNOIS BIOLOGICAL MONOGRAPHS 1204 



EXPLANATION OF PLATE 



Gordius robustus 



Fig. 39. — Cross section in front of cephalic ganglion in specimen shedding the larval cuticula; 

 X90. 



Fig. 40. — Longitudinal section of specimen with adult cuticula nearly completed; shows spine 



in early development with minute fibre barely traceable to hypoderm; X 870. 

 Fig. 41. — Hypoderm and the formation of granular layer under larval cuticula; X 500. 



Fig. 42. — Cross section of specimen with developing cuticula; shows nerve cell and fibre in 

 hypoderm; X 450. 



Fig. 43. — Stage in the development of adult cuticula later than that shown in Fig. 35; cuticula 

 has attained about half its final diameter; X 450. 



Fig. 44. — Late stage in development of adult cuticula, longitudinal section; shows bristle 

 passing thru granular layer; X 665. 



Fig. 45. — Section parallel to neural lamella in specimen nearly mature; shows bipolar cells; 

 X 320. 



Fig. 46. — Cross section thru body of female that has deposited its eggs; shows tissues partly 

 degenerated; X 135. 



