30 



A parasite which promises to be most effective in controlling the 

 black scale is the very odd-shaped little chalcidid fly (fig. 22) known as 

 Scutellista cyanea Motsch. , first found attacking Lecaniwn coffese, in 

 Ceylon. It was later reported by Dr. Berlese as attacking a wax scale 

 {Ceroplastes rusci) in Ital}'. Subsequent to its discovery in Ital}^, vari- 

 ous efforts were made by Dr. Howard, M'ith the assistance of Dr. Ber- 

 lese, to introduce it into Florida and the Gulf districts, particularly 

 as a means of controlling the wax scales. In the meanwhile it was 

 found with the black scale in Cape Colony by Mr. Lo\jnsbury, who, at 

 Dr. Howard's suggestion and with his assistance and the cooperation 

 of different persons in California, notabl}' Mr. Craw and Mr. Ehrhorn, 

 succeeded, in 1900, in getting the parasite into California, where it 

 has been installed under conditions which promise a successful intro- 

 duction of the species. During the last three years it has been con- 

 stantly distributed in California 

 and reports of its work are most 

 favorable. In South Africa, as 

 reported by Mr. Lounsbury, the 

 black scale ver}' rarely is abun- 

 dant enough to be considered at all 

 injurious, and this is apparently 

 due to its parasitism by this little 

 insect. If the latter can be in- 

 duced to play the same role in 

 California the saving will be 

 second only to that accomplished 

 b}^ the Vedalia. 



The remedial measures for the 

 black scale are spraying with the 

 oily emulsions and the gas treat- 

 ment. 



The Soft Scale. 



This scale insect [Lecanium 

 liesiyeridum L. — fig. 23), also 

 known as the turtle-back scale 

 or brown scale, is closely related 

 to the black scale, but is a much 

 softer and more delicate insect. 

 It changes in color with age 

 from a transparent yellow in the young to deepening shades of 

 brown in the adult. The adult scale has a length of 3 or 4 milli- 

 meters, is turtle-shaped, and very much swollen, the body of the 

 mother in the last stages becoming a mere cap filled with young. In 

 the early stages the insect is thin and flat and semitransparent, so 



172 



Fig. 23.— Soft scale {Lecanium hesperidum) : Orange 

 twig showing characteristic massing of the 

 scales — natural size (after Comstock). 



