473 



in the local fauna and iinfaiourable agricultural practices. That 

 this method may be successful in some cases is proved by the complete 

 (:*6rit'rol obtained over the citrus mealy-bug [Pseudococcns citn\ in 

 some orchards in Cahfornia by the continued liberation of large mmibers 

 of enemies, chiefly the Coccinellid, Cryptohemus montrouzieri. 



Ferris (G. F.). Observations on some Mealy-bugs (Hemiptera; 

 Coccidae). — Jl. Eean. Entom., Concord, N.II., xii, no. 4, August 

 1919, pp. 292-299, 3 figs. 



Attention is drawn to the fact that Pseudococcus citrophilus, Claussen, 

 is a synonym of P. gaJiani, Green," described from England on Ribes 

 sanguinea. Tins species has undoubtedly been introduced into 

 California and England, but its original home is not yet known. 



P. maritimus, Ehrh. {bal'eri, Essig), is recorded for the first time 

 from England, where it occurs on various plants in green-houses, and 

 from Florida on sweet potato, tomato and avocado. Other species 

 are P. pint, Kuw., which is reported for the first tnne from California, 

 and is redescribed ; P. hromeliae, Bch., reported from Florida on 

 roots of bananas, pineapples and citrus, and redescribed ; P. virgatus, 

 Ckll., also redescribed, is recorded on Magnolia, mulberry, oleander 

 and an xmdetermined weed from Florida ; and P. comdocki, Kuw., for 

 which a nmnber of food-plants are recorded, seems to have a Avide 

 distribution in the United States and its introduction into California 

 is to be feared. A species already existing in California on Monterey 

 pine very much resembles P. comHochi and is probably a monophagous 

 strain of it. 



The synomymy of other species is discussed. P. guercus, Ehrh., 

 previously erroneously treated as a synonym of P. crawii, proves to 

 be a good species, P. quercicolus, Ferris, being a synonym of it. 

 Lachnodms salicis, Ferris, is a synonym of L. phoradendri, Ckll. ; 

 and Riper sia trichura, Ckll., and Eriococcus salinus, Ehrh., of 

 Cryploripersia arizonensis, Ehrh. 



WoGLUM (R. S.) & Rounds (M. B.). U.S. Bur. Entom. The 

 Stratification of Liquid Hydrocyanic Acid as related to Orchard 

 Fumigation. — Jl. Econ. Entom., Concord, N.H., xii, no. 4, August 

 1919, pp. 300-303, 1 plate. 



The fact that water and hydrocyanic acid have been drawn from 

 the same drmii led to numerous experiments the object of which was 

 to determine whether or not stratification occurs when the two liquids 

 are mixed. Observations of which details are given show tliat this 

 phenomenon always occurs where one Uquid is added slowly to the 

 other irrespective of the order in which they are mixed. The same 

 results were obtained with distilled water as with tap water. 



When hydrocyanic acid was kept in galvanised iron drums and 

 mixed with water, a white precipitate was noticed at the junction 

 of the two fluids, which on examination was found to contain zinc in 

 solution. To avoid stratification only liquids of uniformly high 

 purity should be mixed. It has also been shown that stratification 

 hastens decomposition. 



(G04) o 



