Trombidiformes J 81 



Paul DeBach reports in correspondence that a Bdella sp. occurring 

 commonly on orange trees in Orange County, California, is preda- 

 ceous on collembola. The mite, after capturing its prey by squirting 

 onto it a liquid "silk" and enmeshing its appendages, would suck the 

 body contents. When this mite was eliminated by a DDT application 

 the collembola population increased tremendously. 



The common North American species is Bdella oblonga Say, which 

 is to be found along the east coast, west to Texas and as far south as 

 Panama. It is one of the largest of the Bdellidae, measuring up to about 

 1300 /x in length and can be distinguished by its reticulate inverted 

 U-shaped propodosomal shield. Biscirus lapidarius (Kramer), which 

 is known from Europe and Australia, has also been taken in Mexico. 

 Bdella virgata Ewing is to be found in the United States and Mexico. 



References: 



Baker, E. W., and J. Balock. 1944. Mites of the family Bdellidae. Proc. 



Ent. Soc. Wash. 46(7) : 176-184. 

 Currie, G. A. 1934. The Bdellid mite Biscirus lapidarius Kramer, preda- 

 tory on the lucerne flea Sminthurus viridis L. in Western Australia. 



J. Austral. Council Sci. & Indus. Res. 7(1) :9-20. 

 Grandjean, F. 1938. Observations sur les Bdelles (Acariens). Ann. Soc. 



Ent. France 107:1-24. 

 Thor, Sig. 1931. Bdellidae, Nicoletiellidae, Cryptognathidae. Das Tierreich 



56, pp. 1-65. 

 Womersley, H. 1933. A preliminary account of the Bdellidae (Snout 



Mites) of Australia. Trans. Roy. Soc. South Austral. 57:97-107. 

 . 1933. A possible biological control of the clover springtail or lucerne 



flea {Sminthurus viridis L.) in Western Australia. J. Austral. Council 



Sci. & Indus. Res. 6(2) :83-91. 



Rhagidiidae Oudemans, 1922 



Figures 119-122 



Diagnosis: The rhagidiids are whitish, yellow, or rosy-colored mites. 

 Light-sensitive and fast-moving, they range from small to medium size 

 (0.350 to 1.80 mm.). They are long, delicate, and without armor. A 

 suture separates the propodosoma and hysterosoma. The setae are 

 simple and long. A pair of poorly developed pseudostigmata with only 

 slightly modified sensory setae is located on the propodosoma. Usually 

 eye spots are present. The legs of these mites are relatively long and 

 narrow and have five movable segments. The femora of legs i and ii are 



