December, '09] JOURNAL OP ECONOMIC ENTOMOLOGY 433 



in habit. The accompanying' photograph will convey an idea of its 

 superficial appearance more accurately than description. When 

 many specimens are massed on a plant the filaments are disarranged 

 and intermingled so that the characteristic appearance is somewhat 

 lacking. The mid-dorsal longitudinal brownish band is quite charac- 

 teristic of this species. The microscopical characters of the anal lobes 

 readily distinguish it from adonidum, by the two spines and scattered 

 pores as contrasted with the closely grouped pores in the latter species. 



The ovisacs of citri as w^ell as adonidum are normally of a flattened 

 cylindrical form constructed of loose waxy threads, but when the 

 insects are crowded the ovisacs are irregularly massed. 



This scale has been a pest in citrus groves in southern Europe for 

 many years, and now its damage is assuming alarming proportions in 

 the lemon groves of southern California. Every greenhouse propa- 

 gator knows this insect as a pernicious and aggravating pest. 



The Cottony Maple-Scale 



Pulvinaria vitis (Linn.) 



Coccus vitis Linn., Syst. Nat., Ed. X, 1, p. 456 (1758). 

 Coccus innumerahiUs Rathv., Penn. Farm Journ., p. 256 (1854). 

 Lecanium pyri Fitch (in part), Tr. N. Y. Agr. Soc, p. 809 (1854). 

 Lecanium maclurw Fitch, Country Gentleman, V, p. 38 (1855). 

 Lecanium acericorticis Fitch, 6th Rep. Ins. N. Y., p. 775 (1859). 

 Lecanium acerella Rathv., Lancaster Farmer, p. 101 (1876). 

 Pulvinaria innumerabilis var. occidentalis Ckll., The Entom., XXX, p. 13 

 (1897). 

 Pulvinaria innumerabilis var. tiliw King & Ckll., Psyche, VIII, p. 286 (1898). 

 Pulvinaria hunteri King, Can. Ent., XXXIII, p. 144 (1901). 

 Pulvinaria simplex King, Mitth. Schvv. Ent. Ges. (10), X, p. 475 (1903). 



This is a well known scale in the United States, which in Europe 

 is popularly known as the vine cottony scale. It is one of the most 

 conspicuous scales of this country when the ovisac of the female is 

 fully developed, and is considered a variable pest from year to year. 

 The periodicity of its appearance in dangerous numbers is due directly 

 to the rise and fall in numbers of its parasites and natural enemies. 



This scale is discussed and figured in Bulletin No. 22, n. s., and in 

 Circular No. 64, U. S. Bureau of Entomology, under the name of 

 Pulvinaria innumeraUlis Rathv., but a careful study of our insect in 

 this country reveals absolutely no differences from the common 

 European species, P. vitis (Linn.). Fitch's types have also been 

 compared, resulting in the above synonymy. A study of several sup- 

 posed species and varieties of Pulvinaria, consisting of transplantings 



