86 ILLINOIS BIOLOGICAL MONOGRAPHS [206 



EXPLANATION OF PLATE 



Gordius robustus 



Fig. 47. — ^Three day specimen from I 7; cross section of stylets in tissues of host; X 640. 



Fig. 48. — ^Adjacent section posterior to Fig. 47; cross section of hooks of proboscis in tissues 

 of host; X 640. 



Fig. 49. — Adjacent section posterior to Fig. 48; muscles in proboscis; X 640. 



Fig. 50. — Five day specimen of I 7; section thru anterior end and middle of body in tissues 

 of host; X 480. 



Fig. 51. — Section adjacent to Fig. 50; X 480. 



Fig. 52. — Section adjacent to Fig. 51; X 480. 



Fig. 53. — Section thru extreme ends of same specimen; hooks in proboscis; X 480. 



Fig. 54. — Section of seven day specimen of I 7 in tissues of host; X 225. 



Fig. 55. — Section of nine day specimen of I 7 in tissues of host; X 225. 



Fig. 56. — ^Twenty-eight day specimen of I 8; tangential section thru hypoderm, showing the 

 two rows of nerve cells; X 220. 



Fig. 57. — ^Twelve day specimen of I 7; cross section thru anterior end, showing proboscis mus- 

 cles; X 400. 



Fig. 58. — ^Twenty-eight day specimen of 1 8; cross section near anterior end; X 220. 



Fig. 59. — Sagittal section thru posterior end of young male; anus still opens terminally; X 70. 



