NEW AMERICAN ACARINA. O 



0RIBATIDJ5. 



The following genera are known to me : 



1.— With a tectal plate 2. 



No tectal jilate 6. 



2. — With wings to abdomen 3. 



No wings 5- 



3.— One claw to tarsus Oribalodes. 



Three claws to tarsus 4. 



4. — Tectal plate wholly attached to the ceplialothorax, entire Oribata. 



Tectal plate free at tip, which is more or less deeply cleft Oribatella. 



5.— Tectal plate quite large, free at tip €e|>hus». 



Tectal plate small, wholly attached to cephalothorax Scutovertex. 



6. — One claw to tarsus 7. 



Three claws to tarsus 8. 



7. — Legs much shorter than body, cephalothorax with lateral ridges or wing-like 

 expansions Carabodes. 



Legs slender, posterior pair as long as the body, no wing-like expansions to 



cephalothorax Belba. 



8. — Dorsum composed of concentric rings Liiodes. 



Dorsum different Motlirus. 



ORIBATA Latr. 



With a tectal plate wholly united to the cephalothorax ; abdomen 

 furnished with lateral wing-like expansions ; three claws to the tarsus, 

 the middle one larger than the other two. Body more or less globose, 

 smooth, rarely with bristles ; legs shorter than the body and with 

 fusiform joints, thinly clothed with simple hairs, one near the tip of 

 the penultimate joint being much longer than the others. 



The genus is very rich in species, and some species are very com- 

 mon. The young are soft-bodied mites, sometimes with one or two 

 large, black spots ; upon attaining the adult form it is usually paler 

 and smaller than when really adult. 



1. — With short bristles on abdominal dorsum hirsuta. 



Without bristles 2. 



2. — Wings as high as long, setse very short arborea. 



Wings longer than high 3. 



3. — Wings small, triangular, not projecting in front of abdomen 6. 



Wings large, more rectangular, projecting in front of abdomen 4. 



4. — Lower border of wing emarginate einargiuata. 



Lower border entire 5. 



5. — Abdomen high, convex, a pale spot at base robiista. 



Abdomen depressed, no pale spot •lepressa. 



6. — Abdomen depressed, without any small smooth spots, logs short- . -uicesta. 



Abdomen high, convex, several small smooth spots 7. 



7. — Tectal plate terminated by a distinct transverse ridge pratensis. 



No ridge, only a bristle each side 8. 



8. — No superior bristles, wings more than half as high as long magna. 



Superior bristles present, wings not half as high as long, very small. afliiiis. 



TRANS. AM. ENT. SOC. XXII. JANUARY, 1895. 



