Faraa. D:3 



KKY TO THE APHI'lLMCHIDAK 



The superfamily, Aphelenchoidea, has a single family, Aphelenchidae, 

 which is divided into two subfamilies, Aphelenchinae and Paraphelen- 

 chinae. A key is presented for distinguishing genera of these sub- 

 families which are found in. the soil in association with plant life. 



1. Posterior portion of esophagus not a distinct glandular bulb, 

 esophageal glands considerably overlapping the beginning of 

 the intestine. Aphelenchinae 2. 



Posterior portion of esophagus a distinct structiire contain- 

 ing the esophageal glands and not overlapping the intestine. 

 Paraphelenchinae U. 



2. Head possessing a shallow, sclerotized frontal-disc. (Lat- 

 eral field with 3 incisures, male unknown.) Anomyctus 



Head not possessing a shallow, sclerotized frontal-disc> 3» 



3. Isthmus leading to a more or less distinct posterior portion 

 region about 1/2 to 1/3 length of pre corpus and blending 

 with the beginning of the intestine. Lateral field vrLth 

 10-12 incisures, spicules slender, gubernaculum present, 

 bursa present. Spear without basal knobs. Aphelenchus 



Isthmus comparatively short and blending with beginning of 

 intestine. Longitudinal striae present, characteristic 

 rose-thorn shaped spicules, no gubernaculum, bursa absent. 

 Spear with or without basal knobs. Aphelenchoides 



U, Post-bulbar region of esophagus set-off from intestine by 

 a constriction. Absence of longitudinal striae in lateral 

 fields . Paraphelenchus 



Post-bulbar region of esophagus usually not set-off from 

 intestine by a constriction. Lateral field with 10-12 



incisures with a bulge ventrally on tail region. 



Metaphelenchus 



