420 



Acarology 



Tenuialidae Jacot, 1929 



Figure 356 



Diagnosis: The chelicerae are 

 broad with strong shears. The 

 lamellae are not especially devel- 

 oped. Prolonged anteriorly as 

 plates the pteromorphs extend the 

 length of the opisthosoma without 

 interruptions. Jacot's conception 

 of the pteromorphs places this 

 family into the Pterogasterina. 



Figure 356 Tenuiala mida Ewing. 

 Dorsum of female, legs omitted. 



Genera: 



1. Tenuiala Ewing, 1913 



Type. Tenuiala nuda Ewing, 1913 



2. Hafenrefferia Oudemans, 1906 

 Type. Oribates gilvipes Koch, 1 840 



Oribatulidae Jacot, 1929 



(= Scheloribatidae Grandjean, 1933) 



Figures 357, 358 



Diagnosis: This family belongs with the Pterogasterina. The ptero- 

 morphs lie in one plane only and do not bend ventrally to protect the 

 legs. When seen from above the anterior edge of the pteromorph 

 curves backward. Each genital plate has four setae (an exception is 

 an undescribed species from Panama, which has only the two anterior 

 setae left on each plate) . 



Grandjean 1933 created the family Scheloribatidae for those mites 

 which differed in the anal setal formula in the immature forms in having 

 0-2-3-4-4 in the larval, proto-, deuto-, tritonymphal, and adult stages. 

 Oribatulidae has one seta in the larval stage. When the two groups are 



