Trom b id i form es 211 



Discussion: Andre 1935 states that the Caeculus are predators, slug- 

 gish and slow, to be found in the sun or bare earth and rocks in dry 

 places. In cold periods they take refuge in the moss. When disturbed 

 they play possum. The eight-legged nymphs are similar to the adults 

 but less chitinized; the six-legged larvae are also similar to the other 

 stages. 



Most of the American species have been described by Mulaik 1945, 

 from the southwestern United States. 



References: 



Andre, M. 1935. Notes sur le genre Caeculus Dufour (Acariens) avec 



descriptions d'especes nouvelles africaines. Bull. Soc. d'Hist. Nat. de 



FAfrique du Nord 26:79-127. 

 Jacot, A. P. 1936. Some rake-legged mites of the family Cheyletidae. J. 



N. Y. Ent. Soc. 44:17-31. 

 Lawrence, R. F. 1939. New South African species of the genus Caeculus 



(Acari). J. Linn. Soc. London, Zool. 40(273) :537-545. 

 Mulaik, S. 1945. New mites in the family Caeculidae. Bull. Univ. Utah 



35(17) :l-23. 

 Nevin, F. R. 1943. Caeculus pettiti, a new species of mite from Virginia. 



Ann. Ent. Soc. Amer. 36(3) :389-393. 



Tetranychidae Donnadieu, 1875 



Figures 162-164 



Diagnosis: These mites are plant feeders. They vary in color from 

 yellowish, greenish, orangish, reddish or red, and some are only red in 

 winter. Of medium size, they measure up to 0.80 mm. in length. Pear- 

 shaped, with the narrow portion toward the rear, these mites possess 

 more or less marked shoulders. The propodosoma is not separated or 

 is only weakly separated from the hysterosoma by a weak suture. The 

 dorsal body surface is usually arched, but is flat in Bryobia and Tetra- 

 nycopsis. The skin is soft and has no plates. A pair of eyes is located 

 on each side of the propodosoma. A peritreme is present and at times 

 protrudes. The palpus has a thumb-claw complex. The chelicerae are 

 fused at the base, forming the stylophore and the movable chela is 

 highly modified into a long, whiplike, piercing organ which is charac- 

 teristic for this group (and the Phytoptipalpidae), The tarsi have claws 

 or modified pulvilli. The claws possess tenent hairs and are used in the 

 generic classification of the group. Tarsus i usually has a pair of du- 



