125 
long, oval, with four pairs of legs, and usually a dark spot on each 
side. This latter character, however, is not constant. The general 
color also varies, some mites having a decidedly reddish tint, while 
others are almost colorless. They spin fine webs over the surface 
Fig. 17. Red Spider, Tetraiiychiis 
biijiaculatiis, male, greatl_v 
magnified. 
Fig. 18. Red Spider, TetranycJuts 
biiiiaculatus, female, greatly 
magnified. 
of the leaf — usually on the under side — beneath which they live, 
and it is largely for this reason that they are hard to reach. The 
minute eggs are globular, pale and transparent when deposited, but 
later change to reddish. They are commonly placed on the under 
surface of the leaf, but sometimes on other parts of the plant. The 
young mites mature in about ten or twelve days. 
Remedial Measures. — This pest can usually be held in check, 
or even exterminated, by thoro and timely spraying of the plants 
with water, if the spray is fine and the pressure considerable ; but 
this is a preventive rather than a remedial measure, for, owing to 
the excessive rate of multiplication of the mites in a hot, dry atmos- 
phere, and owing further to the fact that the web beneath which 
they live becomes denser as their numbers increase, the spraying- 
is ineffective unless it is done while the infestation is still slight. 
Indeed, no treatment is of much practical value if the mites have 
become well established on living plants. A special nozzle intro- 
duced by Dr. B. T. Galloway, of the U. S. Department of Agri- 
culture, for use against the red spider is very effective, "as it 
