84 INSECTS AFFECTING THE ORANGE. 



the eyes purplish black. The outline drawing, Fig. 6a, represents the 

 shape of the various organs. 



" Habitat. I have observed this species in several groves at San Ga- 

 briel and Los Angeles, Cal. At the first- named place, where it is very 

 abundant, it is said to have first appeared on a budded orange tree which 

 was purchased by Mr. L. J. Kose, at one of the hot-houses in San Fran- 

 cisco. At Los Angeles it appears to have spread from six lemon trees 

 which were brought from Australia by Don Mateo Keller. 



44 At first I considered this an undescribed species, as I could find no 

 description of it either in American or European entomological publica- 

 tions. I therefore described it in the Canadian Entomologist under the 

 name of Aspidiotus citrL Afterwards I obtained copies of the papers 

 " On some Coccidce in New Zealand," by W. M. Mask ell, published in 

 the Transactions and Proceedings of the New Zealand Institute, and 

 found that he had described an insect infesting oranges and lemons im- 

 ported into New Zealand from Sydney which was either identical with 

 or very closely allied to the red scale of California. I at once sent to 

 Mr. Maskell for specimens of the species described by him. These have 

 just been received and prove to be specifically identical with those in- 

 festing citrus trees in California. Thus the question as to source from 

 which we derived this pest is settled beyond a doubt. 



" I have found Avpidiotus aurantii only on citrus trees. It infests the 

 trunk, limbs, leaves, and fruit. The infested leaves turn yellow, and 

 when badly infested they drop from the tree. This species spreads quite 

 rapidly ; and from what I have seen of it, 1 believe that it is more to 

 be feared than any other scale insect infesting citrus fruits in this 

 country. As illustrating the extent of its ravages in Australia, Dr. 

 Bleasdale told me of a grove of thirty-three acres which nine years ago 

 rented for 1,800 per year, and for which three years ago only 120 

 rent could be obtained. 



" Specimens of this insect colonized on orange trees in the breeding- 

 room of the Department passed through their entire existence in a little 

 more than two months ; hence it is probable that in the open air in 

 Southern California there are at least five generations each year, and 

 possibly six. The mode of the formation of the scale in this species 

 very closely resembles that of A.jicus, described at length in this re- 

 port. The ventral scale, however, reaches a greater degree of develop- 

 ment in A. aurantii than in A. ficus. At first it consists of a very del- 

 icate film upon the leaf; when the second molt occurs it is strengthened 

 by the ventral half of the cast skin, the skin splitting about the margin 

 of the insect, the dorsal half adhering to the dorsal scale and the ventral 

 half to the ventral scale. Later, after the impregnation of the female, 

 the ventral scale becomes firmly attached to the dorsal scale and to the 

 insect 5 so that it is almost impossible to remove an adult female from 

 her scale." 



