NEMATODE DISEASE OF WHEAT. 



17 



phologically, the esophageal portion of the digestive system of the 

 adult is not greatly different from that of the larva except as to 

 size. Behind the posterior swelling of the esophagus, however, 

 there are marked differences both in the 

 intestine and the reproductive system of 

 the adult as compared with those of the 

 larva. In the young female the intestine, 

 occuping a large part of the entire body 

 cavity, becomes proportionately small as 

 the reproductive system increases, so that 

 in old individuals most of the body space 

 is taken up by the egg-producing organ. 

 The intestine is finally pressed closely 

 against the body wall throughout its ante- 

 rior half, while in the posterior portion it 



Fig. 5. — Lateral view of young female 1.95 

 mm. in length. Camera-lucida drawing. 

 X 95. For an explanation of the letters 

 A to J , see figure 6. 



Fig. 6. — Ventral view of young 

 male 1.36 mm. in length. 

 Camera-lucida drawing mag- 

 nified X 95. A, Spear; B, 

 anterior esophageal bulb ; C> 

 esophageal canal ; D, poste- 

 rior esophageal bulb ; E, di- 

 gestive system ; F, reproduc- 

 tive system ;' G, spicula in 

 male and vulva in female; 

 E, anus ; I, bursa of male;; 

 J, tail. 



gradually lessens in diameter and barely touches the wall. Ife 

 contains at first granular bodies as well as liquids, and the entire 

 contents appear yellowish brown in color. In old females, however, 

 151572°— 20 3 



