8. H. schnchtii group. Cyst always with distinct punctation conGiLtinij; 

 oi dots of uniform size but not in rows (fi(j. 25); brown knobs close- 

 ly clustered around vulva. Hyaline portion of larval tail at leact 



one and one-hall' times lon^jer than stylet Heterodfja iTia.jor 



Cyst with or without punctation, mostly in rovfs if present; ui'oini 

 knobs not closely clustered, around vulva. Hyaline portion of lai'vo.l 

 tail about as long as stylet, 9 



9. Average length of larvae ).|80 u or more 10 



Average length of larvie about h60 u Heterodera schpchtii 



10, Average length of larvae [l8U u Heterodera ''lyc inGs 



Average length of larvae i>02 u. Heterodera trifolii 



Average length of larvae 5l8 u, . . . Heterodera schachtii galeo p sidis 



11, Average length of larvae U1I4 u Heterod era cru ci rerao 



Average length of larvae hS\\ u « Hetei"odcr-i c nrotae 



Average length of larvae i47l4 u Heterodera gottin'iana 



Average length of larvae i;05 u Heterodera hwiu lL 



/Average length of larvae hPS u Heterodera fici 



Plate I, Shapes of cysts of Heterodera species. Fig. 1. 



H. rostochiensis . Fig, 2, H. punctata . Fig, 3, H. schachtii 

 Fig, U, H. avenae . Fig, 5. H. weissi, Fig. 6. H. cacti, 



Plate II, Cyst patterns of Heterodera schachtii and related species. 



Figs. 7 and 8. Zig-zag line pattern near middle of cysts of 

 H, trifolii and H. schachtii respectively. Fig. 9. Pattern 

 at junction of neck and body of cysts of H. schachtii . Fig. 

 10. Pattern near vulva of cyst of H. gottingiana . Fig. 11, 

 Sheaf -shaped object and dark bodies at lower end of cyst of 

 H, schachtii . Fig. 12. Netx-iork pattern, a variation of that 

 shown in Figs. 7 and 8. Magnification of figure 11 is about 

 200X, all other about UlOX. 



Plate III, Cyst markings of Heterodera weissi and H. cacti . Fig. 13. 



Lower part of cyst of H. cacti . Fig, 1I4, Pattern near middle 

 of cyst of H, weissi . Fig. 15, Pattern at junction of body 

 and neck of H, weissi . Fig, I6, Pattern near middle of cysts 

 of H, cacti . Fig. 17, Loxjer end of cysts of H, cacti showing 

 anus. Fig, 18, Grainy appearance of cyst of H. cacti . All 

 about UlOX, 



Plate IV, Cyst patterns and punctation of Heterodera rostochiensis and 

 H, punctata . Fig. 19. Pattern at vulva and anus of H. 

 rostochiensis . Fig, 20. Same as Fig. 19, but with deeper 

 focus to show punctation. Fig, 21. Anal and vulvar openings 

 of cyst of H, punctata . (Cyst split in process of prepara- 

 tion). Fig, 22. Pattern at about middle of cyst of H. 

 rostochiensis . Fig, 23. Pattern of upper part of cyst of H. 

 punctata . Fig, 2U, Punctation of H. rostochiensis . All 

 about UIOX. 



Plate V, Cysts and eggs of Heterodera species. Fig, 25, Punctation of 

 cyst of H, avenae , Fig, 26, Punctation and pattern of cyst 

 of H, hujnuli. Fig, 27. Punctation of cyst of H. trifolii . 

 Fig. 2jr, Punctation of egg shell of H. cacti. 



