409 



The chemical composition of the mixture is very complex and still 

 micertain, but it may be assumed that it is a solution of calcium 

 tetrasulphide and pentasulphide with small quantities of hyposulphite. 



The action of polysulphides on plant pests has in some cases been 

 attributed to the action of sulphur vapour and in others to oxidation 

 of the sulphur, with the production of sulphur dioxide. Polysulphides 

 rapidly extract the oxygen from insects, thus disorganising their 

 tissues, and even leading to asphyxiation. The production of sulphur- 

 etted hydrogen by the action of the carbon dioxide of the air should 

 also be considered. 



The following insects may be successfully dealt with by using this 

 substance : Tetranychiis ielarius, T. mytilaspidis, Chrysomphalus 

 dictyospermi, Ceroplastes rusci (fig scale), Eulecanium {Lecanium) 

 persicae (peach scale), Saissetia oleae (black scale), Eriosoma [Schizo- 

 neiira) lanigeriim, Hyponomeuta vialinellus and Cydia (Carpocapsa) 

 pomonella, as well as various fungus diseases. 



Starting with a basal mixture at 21°-24° Be., spraying in winter 

 should be done with 8-10 per cent, strength and in spring and summer 

 5-6 per cent. As the density is 35°-40° Be., from 29 to 40 parts of the 

 mixture should be used per 1,000 of water in winter and 18 to 20 parts 

 for spring and summer use. 



Weiss (H. B). Popular and Practical Entomology : The Apple LeaJ- 



crumpler as a Pest of Cotoneastcr. — Canadian Ent., Giielph, 



liii, no. 4, April 1921, pp. 73-75. 

 Mineola indiginella, Z., is recorded from New Jersey as feeding on 

 ornamental shrubs [Cotoneaster microphylla and C. horizontalis) . There 

 is only one brood during the year. The eggs are laid in July, and the 

 resulting larvae hibernate. They become full-grown about the first 

 or second week in June. A description of the larva is given. The 

 moth is parasitised to some extent by Tachina phycitae, Le B. 

 Arsenicals applied to the plants early, as in the case of apples, should 

 prove effective. 



Bird (H.). New Species and Life-histories in Papaipema, Sm. 

 (Lepidoptera) no. 20. — Canadian Ent.,Gitelph, liii, no. 4, April 1921, 

 pp. 79-81. 

 Superficial observations have frequently resulted in the confusion 

 of injury to maize by Papaipema nebris, Gn., with that by Pyrausta 

 niibilalis, Hb. (European corn borer). The favourite food-plants of 

 P. nebris belong to the Ambrosiaceae, especially Ambrosia trifida. 

 These weeds are frequently found on the borders of cultivated fields, 

 and should the original food-plant not be sufficient for the numerous 

 larvae, they will readily turn their attention to maize. They descend 

 into the head of the leaf whorl and prevent the ear from maturing 

 by destroying the embryonic flower head. This moth is able to 

 complete its life-cycle on maize. Although it is heavily parasitised 

 by Masicera senilis, Mg., and Microplitis gortynae, Riley, when feeding 

 on Ambrosia spp., these natural enemies apparently do not follow 

 it to maize, and it may therefore become a pest of serious economic 

 importance. 



Baker (A. C). U.S. Bur. Ent. Note on the Rosy Aphis. — Canadian 

 Ent., Guelph, liii, no. 4, April 1921, p. 95. 

 Recent examinations of the type of Aphis malifoliac, Fitch, prove 

 this species to be a synonym of A. crataegifoliae , Fitch. The rosy 

 apple aphis recorded as A. malifoliae [R.A.E., A, v, 49, 550, etc.] is 

 therefore now given the name of Annr aphis roseus. 



(3719) 2 F 



