SYSTEMATIC POSITION AND EELATIONSHIPS. 55 



safely identified from the appearance of the scale covering and with- 

 out being" prepared for microscopical study. 



Three varieties of the San Jose scale have been designated, none of 

 which are valid. Of these Asjjidiotus perniciosus var. albopunctatus 

 Ckll. was described from twigs of a supposed orange seedling sent 

 from Japan and stopt by Mr. Craw in his quarantine work in San 

 Francisco. The twigs are thorny and ma}^ possibly be of the trifoliate 

 orange or of some orange seedling, but whether of ordinary orange 

 or tangerine or some other horticultural variety can not be determined. 

 From the extreme unlikelihood of the San Jose scale attacking ordi- 

 nary orange, the probabilit}^ is very strong that these seedlings were 

 either trifoliate or of the mandarin or tangerine tj pes. At an^^ rate, 

 the scale itself is t3"pical San Jose scale, and there is no basis what- 

 ever for tl e separation of these specimens as a variet3\ The character 

 on which the variet}^ was founded, namely, the wdiite dot surrounded 

 by a black ring marking the exuvia, is a feature which may be very 

 commonl}^ found in the San Jose scale from any source. 



The other variety established by Mr. Cockerell is his Aspidiotus 

 perniciosus var. cmdromelas^ first described in California Fruit Grower, 

 June 5, 1897, on a plant labeled ^^ Phmtenia glauca^^^ from Japan, also 

 received from Mr. Craw. This variety is also based on the character 

 of the covering scale, and is described as wholly black without any 

 light dot and ring, a condition which is easily produced b}^ rubbing or 

 otherwise accidentally and may occur anywhere. 



A third synonym of the San Jose scale is MaskelFs species Asjn- 

 diotits fusca^ described in the New Zealand Transactions, Volume 

 XXVII, pagCttS, 1891, figures 6-9, Plate I. This insect was described 

 from material collected in Australia on peach; and from MaskelPs own 

 figures and account of it, and also from the study made b}^ Leonardi 

 in Italy, and from the later note on the subject by Maskell himself in 

 the Canadian Entomologist, it is evident that this species was based 

 on material ]*epresenting the last stage of the female of perniciosiis^ 

 but before the secretionar}^ supplement had been much if any devel- 

 oped, so that the second exuvium w^as still larger than the newlj^ 

 molted insect. This point can not, of course, be fully determined 

 without an examination of type material, but there is very little doubt 

 in the writers mind of the correctness of this reference. 



A fourth variety is Aspidiotus jjerniciosiis var. eitcalypti YwWqt. 

 A study of material received from Fuller of this variety indicates that 

 it should not be referred to the San Jose scale at all, but is a good 

 distinct species belonging to the genus Aonidiella, and the name 

 becomes Aonidiella eucalypti Fuller. 



No valid varieties or subspecies of the San Jose scale have therefore 

 been found, and all of the points of infestation now known can be 

 traced directly to the Chinese origin of the scale. 



