58 THE SAN JOSE OR CHINESE SCALE, 



slow where trees are raoderatel}' widely separated, and usually an 

 entire orchard will not become affected from a single original point 

 for several years. 



Occasionally the 3'oung scales may be locally transported b}^ men or 

 teams. An interesting case in point is given by Professor Rolfs. He 

 states that some melons growing in an infested orchard were given b}" 

 the owner to a friend, who took them away from the orchard in his 

 wagon. A year later the scale developed on a tree under which the 

 team had been hitched while the melons were unloaded. As this 

 orchard was entirel}" free from the scale originall3% it seems to be a 

 reasonable inference that the young had crawled upon the wagon, 

 harness, or melons, were conve^^ed a distance of 3 miles, and suc- 

 ceeded in gaining access to a tree which probably touched the wagon 

 or team during the interval of unloading. 



PARASITES AND OTHER NATURAL ENEMIES. 



The following paragraphs, under the heading- ''True parasites," 

 were prepared for this bulletin by Dr. L. O. Howard. 



• TRUE PARASITES. 



Some eight species of true parasites have been reared from the San 

 Jose scale in this country. NearW all of these are widespread, occur- 

 ring on the Pacific coast, and generally also in the East, and are found 

 also in other parts of the world. None of them are specific enemies 

 of the San Jose scale in the sense that the}" are limited to this species 

 of scale, but all of them are general parasites on other armored scale 

 insects. They are as follows: 



Aj)hclinus fiiscipennis Howard. 



Ajjhelinus mytilasjndis Le Baron. 



Aspidiotiphagus citrinus Howard. 



Ancq)hes gracilis Howard. 



PJiyscus varicornis Howard. 



Prospalta aurantii Howard. 



Ahlenis clisiocampce Ash mead. 



Rhopoideus citrinus Howard. 

 Of these Aspidiotiphagus citrinus^ Prospalta aurantii^ Aphelimts 

 fuscipennis^ and Aphelinus mytilasp)idis are of very wide distribution. 

 Aspidiotiphagus citrinus^ for example, originalh" described from Cali- 

 fornia in 1891, is now found in man}" other portions of the United 

 States, in the West Indies, Italy, Austria, Ceylon, China, Formosa, 

 Japan, Cape Colony, Queensland, South Australia, and Hawaii, and 

 this remarkable distribution is practically followed by the other three. 

 The most important of these parasites is the little Apheliniis fusci- 

 yennis. It was reared in large numbers by Mr. Coquillett, in Califor- 

 nia, many years ago, where it was found to breed- thruout the year, 



I 



