: 3 
ern California; and in 1908 at Brownsville, Tex., this last locality 
practically assuring its occurrence in Mexico.* 
NATURE OF INJURY. 
The red spider occurs in greenhouses throughout the year, and 
appears to be at all times destructive if permitted to propagate. 
Few plants are, in fact, free from its attack, and it is found in most 
greenhouses. When only a few mites are present the plants seldom 
show any external evidences of injury, but as they increase in number 
the leaves gradually turn paler and become yellowish and stunted, 
and soon the whole plant succumbs unless the proper remedies are 
applied. Cuttings or young rooted plants are particularly subject 
to serious injury, and this is especially true in the spring. At this 
time the mites multiply rapidly, and unless plants are carefully 
watched they are apt to become so badly infested that it is only with 
extreme difficulty that they can be restored to their normal growing 
condition. : 
The mites injure plants by suction, and when they oceur in num- 
bers, which they almost assuredly do when plants are neglected, the 
vitality of the plants is slowly but surely reduced by the loss of 
the juices, and in time all of the plants’ functions are more or less 
deranged. In cases of severe attack, millions of red spiders can be 
found upon the foliage, and the webs, rarely observable at ordinary 
times, sometimes stretch from plant to plant, the mites passing rap- 
idly over them and congregating in swarms. 
FOOD PLANTS. 
The red spider is nearly omnivorous, attacking a wide range of 
both glabrous and hirsute plants belonging to many families. It has 
been observed on plants of the following list: Among greenhouse and 
other ornamental plants, roses, violets, carnations or pinks, mignon- 
ette, clematis, pelargonium, abutilon, fuschia, passiflora, manettia, 
bouvardia, feverfew, verbena, heliotrope, salvia or sage, morning- 
glory, moonflower, cypress-vine, phlox, chrysanthemum, calla, Easter 
lily, Boston smilax, mimulus, shipper flower (Calceolaria), canary 
bird (Tropwolium peregrinum), thaunbergia, wedding bells (Brug- 
mansia arborea), castor-oil plant, Asparagoides plumosa, cuphea, 
godelia, sunflower, and aster. Of the plants listed, violets and roses 
are very susceptible to damage by the red spider, more especially 
when the plants are growing under glass. 
“Tf, as seems probable, Tetranychus cucumeris or some other species described 
by Boisduval (Entom. Horticole) is identical with 7. bimaculatus, it is quite 
likely that this red spider is of foreign origin and introduced into the United 
States, which is true of a very large proportion of greenhouse and other indoor 
insects. 
[Cir. 104] 
