6 



two years it has been more severe than during the previous twenty 

 years ; chewing insects are usually better controlled by the use of 

 dry poison, but, not being abundant in 1916-17, their control could 

 not counterbalance the poorer control of scab ; if under such conditions 

 growers are satisfied with the results obtained, they will be better 

 satisfied in years when scab is not so abundant and when insects are 

 likely to be more prevalent ; the method of applying dust is not well 

 understood, and the dust machines now in use may be open to as 

 much improvement as the old barrel sprayer was ; the dust method 

 makes it possible for any grower to follow a new schedule for orchard 

 protection, consisting of light treatments at more frequent intervals, 

 it being possible to make an application of dust to the entire orchard 

 before the condition actually permitting infection arrives ; the great 

 saving of time effected by dusting makes growers anxious to experiment 

 in the hope of finding improved methods. 



In the opinion of the author the factor most likely to determine 

 the future success or failure of dusting is the discovery or non-discovery 

 of dry, contact insecticides, since at present a spray machine must 

 be kept for use against scale-insects, Aphids and red bugs. 



In the discussion that followed, the points most emphasised were 

 the immense saving in time and labour effected by dusting, and the 

 great adhesive qualities of a mixture of 85 parts sulphur and 15 parts 

 lead arsenate. 



Baker (A. C). Another Toxoptera feeding on Sedge (Homoptera; 

 Aphididae). — Psyche, Boston, Mass., xxv, no. 4, August 1918, 

 pp. 88-93. [Received 31st October 1918.] 



Toxoptera nigra, sp. n., is described. Apterous forms of this Aphid 

 were found on sedges growing in marshy land in the' District of 

 Columbia and the species is described from individuals reared from 

 these. 



DE Seabra (A. F.). Observations sur quelques Esp^ces de Cochenilles 

 du Portugal. [Observations on some Species of Coccids from 

 Portugal.] — Bull. Soc. Portugaise Sci. Nat., Lisbon, viii, no. 1, 

 1918, pp. 72-81. 



An account is given of the Coccidae of Portugal. Twenty-six 

 species, of which three are unidentified, are mentioned. These are : — 

 Icerya purchasi. Mask., which is checked to a large extent by Novius 

 cardinalis, imported from America ; Psewlococcus (Dactylojmis) citri, 

 Risso ; P. adonidum, L. (Z). longispinus, Targ.), which was considered 

 to be the cause of a heavy infestation of the elm trees in the streets 

 of Lisbon, and for which several insecticides have been tried without 

 success ; Orthezia urticae, L. , apparently not very numerous or harmful ; 

 Kermes rohoris, Fourc. {variegatus, Gmel.) ; Lichtensia viburni, Sign. ; 

 Pulvinaria vitis, L. ; P. camelicola. Sign ; Ceroplastes nisei, L., found 

 wherever figs are grown in Portugal and frequently destroyed b}^ the 

 Coccinellid, Chilocorus renipustulalus ; Coccus {Lecanium) hesperidum, 

 L. ; Saissetia {Lecanium) hemispJiaerica; Targ. ; S. oleae, Bern. ; 

 Lecanium signiferum, Green ? ; Aspidiotus camelliae. Sign. ; 

 A. cydoniae, Comst. ; A. palmae, Morg. ; A. hederae, Vallot, which 

 is injurious to olive trees ; two unidentified species of Aspidiotus ; 



