THE RED SPIDER ON COTTON. 35 
Chittenden (1909) observed larve of Scymnus punctum, Cecidomyra 
coccidarum, Chrysopa rufilabris, and all stages of Thrips seemaculatus 
to be predatory on red spiders on the Kentucky coflee tree (@ymno- 
cladus dioica) at Washington, D. C., during July and August, 1906. 
He states that the Scymnus larve were the most effective. In Colo- 
rado, Weldon (1909) found lacewing-fly larvee and Scymnus punc- 
tum to be the principal enemies of the red spider. Worsham (1910) 
states that the only natural enemy observed during the studies in 
Georgia was Stethorus punctum, which fed, both in the larval and 
adult forms, on the mites and the eggs. It was Quayle (1913) who 
first gave us a considerable list of red-spider enemies. He does not, 
however, differentiate between the predators of T. mytilaspidis, T. 
sexmaculatus, and T. bimaculatus. He states that most of the obser- 
vations were made on the citrus mite. Parker’s investigations (1913) 
in central California during 1911 and 1912 revealed the presence of 
the following predators, which he states he has seen preying upon 
red spiders: Triphleps tristicolor (nymph and adult), Scymnus nanus, 
Scymnus margimecollis, Pentilia sp., and Chrysopa californica. The 
lacewing-fly larvee were most active. Finally, Ewing (1914) lists the 
following species as actively predatory on the red spider in Oregon: 
the mite Sews pom, Triphleps insidiosus, syrphus-fly larve, and 
Stethorus punctum. Other species of mites and insects are men- 
tioned by Ewing either as having been reported elsewhere on the 
Pacific Coast or as being probable enemies. Ewing estimates Seius 
to be the most valuable red-spider enemy in Oregon. All told, these 
enemies of the common red spider make a total of a dozen species 
which, to date, have been reported as definitely feeding upon Tetra- 
nychus bymaculatus. Neither Parker nor Ewing appears to believe 
that substantial control accrues from the activities of the red-spider 
enemies. 
In the case of each of the seasons 1911, 1912, 1913, and 1914, 
during which the red spider has been under observation at Bates- 
burg, S. C., a sudden decimation of a more or less complete nature 
has occurred. Figure 8, page 26, presents a diagram whichconsists of a 
composite curve representing the average seasonal status of the red 
spider in South Carolina for 4 years. The low summer point, reached 
in July, indicates graphically the combined control value of predatory 
species. The red spider at the present time is known to be the 
host of 31 species of arthropod enemies. Of these, 5 are mites 
(Acarina), 3 are thrips (Thysanoptera), 4 are bugs (Hemiptera), 4 
are lacewing flies (Neuroptera), 2 are midges (Diptera), 4 are syrphid 
flies (Diptera), 8 are lady-beetles (Coleoptera), and 1 is a noctuid 
- moth (Lepidoptera). These predators, in turn, are known to be 
attacked by 75 species of predators and parasites. 
