Trombidiformes 241 



the insect. These mites also prey on red scale crawlers and other small 

 insects and mites. If more abundant they might be an important enemy 

 of the red scale." 



An interesting erythraeid mite is Ptilophus namaqiiensis (Lawrence) 

 which is from South Africa. The posterior pair of legs are rather 

 long and the tibia is furnished with a large plume of long setae. The 

 mites hold these legs, when running, either horizontally behind them 

 or vertical, not using them for locomotion. The mite runs very rapidly 

 and vibrates this last pair of legs. Several functions of this posterior 

 pair of legs have been proposed by Lawrence 1937 — (a) an aid in 

 locomotion, (b) sensory, (c) defence, (d) sexual. 



Rejerences: 



Ebeling, W. 1934. A new predaceous mite from southern California. Pan- 

 Pacific Ent. 10(l):33-34. 



Grandjean, F. 1947. Etude sur les Smarididae et quelques autres Ery- 

 throides (Acariens). Arch, de Zool. Expt. et Gen. 85(1):1-126. 



Lawrence, R. F. 1937. A new species of plume-footed mite from South 

 Africa. Ann. South African Mus. 32(3) : 269-279. 



. 1940. New larval forms of South African mites from arthropod 



hosts. Ann. Natal Mus. 9(3) :401-408. 



Southcott, R. V. 1946. Studies on Australian Erythraeidae (Acarina). 

 Proc. Linn. Soc. New South Wales 71 ( 1-2) :6-48. 



Smaridiidae Kramer, 1878 



Figures 178, 179 



Diagnosis: These mites have a longish, oval body which is pointed 

 anteriorly and moderate shoulders. The propodosoma is usually drawn 

 out into a long "nose" and a shallow furrow separates it from the 

 hysterosoma. The dorsal surface of body is slightly convex and occa- 

 sionally has several longitudinal and transverse depressions. Two sen- 

 sillary areas, each with a pair of sensory setae, are located on the 

 dorsum of the propodosoma. The crista metopica may be present or 

 absent. One or two eyes are situated on each side of the propodosoma. 

 The setae are of peculiar structure; they are usually in the shape of 

 a leaf with thorns or hairs which are strongly curved and folded longi- 

 tudinally. Coxae I and ii, and iii and iv are united, but the two groups 

 are separated. The legs are slender, occasionally extremely long, and 

 have six movable segments. Two claws are present on the tarsi but 



