PREDACEOUS ENEMIES. 19 
the clusters were blown from 6 to 8 inches from where they would 
naturally drop, but it is very unlikely that they are carried any 
distance by any but a very strong wind. 
The only probable means of distribution other than the natural 
migrations are by horses used in cultivating, or by the hands and 
clothing of the men, and possibly on the bodies of the larger insects 
found on the hopvines. 
PREDACEOUS ENEMIES. 
Several predaceous insects were observed destroying red spiders on 
the hopvines near Sacramento, Cal., but their numbers were insuffi- 
cient to have any effect upon the infestation. The most numerous 
predaceous insect was a small anthocorid bug ( Triphleps tristicolor 
White) . This insect, both in the nymphal and adult stages, was very 
common in some sections of the yards and was frequently seen feeding 
on the mites. 
Certain small ladybirds have been noticed preying upon this species 
in infested yards, but were not found in large numbers. Among these 
are the following : 
Scymnus nanus Lee, observed at Sacramento, Cal., July, 1911. 
Scymnus marginicollis Mann., observed at the same time and place. 
Pentilia sp., found in some infested yards but present only in small numbers. 
During July Chrysopa calif ornica Coq., in the larval stage, was very 
abundant and probably did more good than all the rest of the pre- 
daceous insects together. 
Dr. F. H. Chittenden 1 reports (Scymnus) Stethorus punctum Lee, 
Cecidomyia coccidarum Ckll., Aplianogmus varipes Ashm., Chrysopa 
rufilabris Burm., and (Tlirips) Scoloihrips sexmaculatus Perg. as feed- 
ing upon the red spider at Washington, D. C, and elsewhere., 
Mr. E. A. McGregor, 2 an agent of this bureau, has recorded the fol- 
lowing natural enemies of the red spider on cotton at Batesburg, 
S. C, in 1912: 
Triphleps insidiosus Say. 
Chrysopid larvae. 
Euthrips fuscus Hinds. 
Euthrips occidentalis Perg. 
Scolothrips sexmaculatus Perg., recorded by both Pergande and Duffy. 
Coccinella 9-notata Hbst. (larvae). 
Hippodamia convergens Guer. (larvae). 
While predaceous insects destroy many of the mites in the hop 
fields, their work has no appreciable effect upon the infestation. 
1 The common red spicier, Cir. 104, Bur. Ent., U. S. Dept. Agr., 1909. 
2 The red spider on cotton, Cir. 150, Bur. Ent., U. S. Dept. Agr., 1912. 
