212 



Acarology 



plex sensory setae. No genital suckers are present. The males possess 

 genitalia which are useful in species identification. 



The spider mites receive their name from their ability to spin a 

 fine web over the leaves of the plant upon which they feed, and at 



Figure 162 Metatetranychus iilmi 

 (Koch). Dorsum of female. 



Figure 163 Metatetranychus iilmi 

 (Koch). Dorsum of male. 



times the entire plant may be covered by this webbing. Blauvelt 1945 

 describes the silk glands as consisting of two groups, the tubular silk 

 glands and the reniform silk glands, both of which empty into a 

 common duct in the rostrum. Geijskes 1939 states that Tetranychus, 

 Eotetranychus, Amphitetranychus and Schizotetranychus spin freely; 



Figure 164 Metatetranychus ulmi (Koch). Upper row, tip of tarsus, egg; lower 

 row, tip of palpus, aedeagus. 



