THE MONTHLY BULLETIN. 395 



THE DICTYOSPERMUM SCALE. 



Chri/soiiiphdlKs dictyospermi ( Morgan ) . 

 Aspidiotus dittiiiisixriui Morgan, lOnt. Mon. Maj;., VoL XXV, p. 352, 188'J. 



(Figs. 68, 69, 70.) 



This scale has a very wide distribulioii througliout the tropical and 

 subtr()i)ical world and occurs in greenhouses in many parts of the 

 tempei-ate regions. It has been foun.d in many places in the United 

 States and has a limited distribution in California, but only in green- 

 houses or very mild and protected places. It was first reported bj^ the 

 United States Department of Agriculture (Bureau of Entomology) in 

 this State in 1909.' A variety, (JJirijsouiiihaluH dicti/ospermi arecm 

 (Newstead) was taken by Mr. B. B. Whitney on orchids in Golden Gate 

 Park, San Francisco, in 1913.** In 1915, County Horticultural Com- 

 missioner A. A. Brock took the species on a few kentia palms in Ven- 

 tura,** and the plants were destroyed at the time. The writer finds it 

 abundant now on kentia palms in the greenhouse on the campus of 

 the University of California at Berkeley. 



The writer has also received specimens taken on kentia palms taken 

 at Marysville by G. W. Harney (November 1, 1915), and at San Diego 

 (November 19, 1915). There are specimens in the collection of the 

 University on avocado taken at the University greenhouse. 



The scales of the females (Fig. 68) vary from light grayish-white 

 to reddish or amber-brown, and are circular or slightly elongated, with 

 the exuviae central or subcentral, depressed or nipple-like and from 

 light-yellow to reddish-brown in color. The exuviae may or may not 

 be surrounded by a depression or ring-like ridge. 



The bodies of the females (Fig. 69) are oval, or somewhat tapering 

 towards the posteiior end, especially in the immature forms. There 

 are three pairs of distinct lobes on the pygidium (Fig. 70), as follows: 

 the median pair large with a notch on the outside margin near the 

 middle; second pair nearly as large, with notch on the outer margin 

 near the middle ; third pair much smaller, with one or two notches on 

 the outer margin. There are two divided plates, or pectinte, between 

 the median lobes, two between the median and second pairs, three 

 between the second and third pairs, and foUovring the third pair there 

 are three very large conspicuous ones with enlarged bases, which 

 greatly aid in distinguishing the species. There are four prominent 

 dark linear areas, or paraphyses, at the bases of the lobes as shown in 

 illustration (Fig. 70). The posterior circumgenital pores consist of 

 from two to three in each group and the anterior from three to four. 



The recorded food plants in this State are kentia palms,^" orchids" 

 and Calofujuc crislnte.^- It has also been taken on avocado in the 

 TTni versify greenhouse, as already stated. In other regions it has been 

 found to attack the following plants as well as those already listed: 



'Baker and Essig, P. Jr. Ent., Vol. I, pp. 58, 61, 1909; also Monthly Bui. Cal. Hort. 

 Com., Vol. I, No. 10, pp. 747, 751, 1912. 



*Monthlv Hul. Cal. Hort. Com., Vol. II. p. 58:5, 1913. 



''Monthly Bui. Cal. Hort. Com., Vol. IV, p. 116, 1915. 



"Baker and Essig. P. Jr. Ent., Vol. I, p. 61. 1909. 



"'Whitney, B. B., Monthly Bui. Cal. Hort. Com., Vol. II, p. 5S.3, VMZ. 



»2Baker and Essig, P. Jr. Ent., Vol. I, p. 58, 1909. 



