86 ILUNOIS BIOLOGICAL MONOGRAPHS (206 



EXPLANATION OF PLATE 



Gordius robustus 

 Fig. 47. — Three day spedmen from 1 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 spedmen of I 8; tangential section thru hyjxxierm, 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- 



des; X 400. 

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

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



