APPENDIX. 375 



ubundant upou pears, attracted by the juices emergiuji frcuu cracks, and 

 almost every one of these insects carried on its back one or more specimens 

 of the young scale insects. Specimens of the little chrysomelid beetle, 

 Typophorus canellus, were also found upon the trees. Both red and black 

 specimens of this beetle occurred, and the interestinof observation was made 

 that while Aspidiotus larva? crawled freely on the black individuals no 

 specimens were to be found upon the red ones. The same peculiarity was 

 found to hold true with the ants. The red ant, Formica schaufussi, was 

 abundant upon the pears but no specimens were found bearing Aspidiotus 

 larvae, while, as just stated, the little black Monomorium was always found 

 carrying them. 



As illustrating this transportation of the scale by birds or insects the 

 experience at Rivei*ide, Maryland ( ante, p. 25 ), may be cited, and Professor 

 Smith reports a similar instance in New Jersey, in letter of January 13, 1896. 



In spite of the abundance of insects which may transport the larvae the 

 progress of the scale from infested trees to noninfested trees is slow where 

 trees are moderately widely separated, and usually an entire orchard will 

 not become affected from a single original point for several years. 



Occasionally the young scales may be locally transported by 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 by the owner to a 

 friend, who took them away from the oi-chard 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 entirely free from the scale 

 originally it seems to be a reasonable inference that the young had crawled 

 upon the wagon, harness, or melons, were conveyed a distance of three 

 miles, and succeeded in gaining access to a tree which probably touched the 

 wagon or team during the interval of unloading. 



TllK PAKASITES AND XATUKAL KNEMIES. 



TRUE PARASITES. 



Of true parasites three have been reared from the San Jose scale in 

 California and three in the east, two of the latter being the same as two of 

 those occurring on the Pacific Slope. The most important parasite perhaps 

 is Ajjhelinus fusciiJennis How., a common and widespread enemy of armored 

 scales. The general characteristics of fuxcqicnnis are well shown in the 

 accompanying figure of a closely allied species (Fig. 7). This parasite has 

 been reared in large numbers by Mr. Coquillett in California, where he 

 found it to breed throughout the year, obtaining specimens as late us 

 November 10. In the east several specimens of this insect have been reared 

 by Professor Smith in New Jersey, and we have found scales at Riverside, 

 Maryland, and Charlottesville, Virginia, pierced with holes which were 

 probably made by this species. The two other western parasites were 

 ^^eared by Mr. E. M. Ehrhorn in Santa Clara County, California, and are 

 Apihelinus mytilaspidis Le B. and Aspidiotlphagus citrinus Craw. The other 



