66. 



lU. Postvulvar uterine sac ahsentj bursa extending far down tail 



graminophila Goodey, 1933 Filipjev, 1936 



Postvulvar uterine sac present; bursa extendinf^ about half way dovm 

 the tail balsamophilus (Thorne, 1926) Filipjev, 1936 



15. Median esophageal bulb inconspicuous; male tail with mucro; male 

 slightly longer than female, the former not surpassing 1 mm. 



..... durus (Cobb, 1922) Filipjev, 1936 



Median esophageal bulb distinct; male tail without mucro; female 

 distinctly longer than male, having a length of 2.5 mm 



. pinophila (Thome, 1935) Filipjev, 1936 



16. Tail short, only l|- times as long as anal body diameter 17 



Tail medium, 2^ timas as long as anal body diameter 18 



17. Head not distinctly offset; spear 1/10 of esoohageal length 



,....,,..... majo r (Fuchs, 1914) Filipjev, 1936 



Head distinctly offset; spear 1/15 of esophageal length 



......... gallica (Steiner, 1935) Filipjev, 1936 



18. Buccal spear 1/20 of esophageal length 



. . dendrophilus (Marcinorvsky, 1909 ) Filipjev, 1^36 



Buccal spear 1/12 of esophageal length ortus Fuchs, 1938 



Other species: 



D. askenasyi (Butschli, 1873) Goodey, 1951 



D. brenani (Goodey, 19i45) Goodey, 1951 



D. sycobius (Cotte, 1920) Filipjev, 1936 



r?) D. brevi Cauda (Micol., 1925) Filipjev, 1936 



Genus Psilenchus de Han, 1921 

 (Key to species laodified Iroia Thoi-ne, 19li9) 



1. "Mo ovaries present 2 



One ovary present .,.,,..,,,,, 5 



2. Spear with small basal knobs, tail clava+e 



• . . clavicaudatus (Micol., 1922) Thorne, I9U9 



Spear without basal knobs , 3 



3. Tail terminus filiform, lip region not striated 



t erext remus Hagemyer & Allen, 1953 



Tail terminus lulbous or clavate T , I4 



U, lap region striated .».,.... striatuj Thorne, 1919 



Lip region plain, not striated hilar'ulus de Han, 1921 



5. Spear plain without basal knobs .,..,.., magni dens Thorne, 19h9 

 Spear -vath di stinct bapal knobs , , , . V ,6 



6. Spear curved, knobs asymmetrical. . , , aberrans Thorne, 19 h9 



Spear straight, knobs symmetrical ,.,,... .^jracilis Thorne, 19h9 



