48 



Douglas, who originally identified it as L. acuminatum of Signoret, that upon closer 

 examination he considers it to be a distinct species. At his request I have accord- 

 ingly described it as a new species in the April (No. 299) Entomologists' Monthly 

 Magazine under the name of Lecanium mangiferce. Mr. Douglas appends a note to 

 this article-in which he mentions that the specimens received from Demerara should 

 also be referred to this species. 



From small experiments with kerosene soap emulsions I feel sure that your pro- 

 posed remedy would successfully exterminate the scale-bug so destructive to our 

 coffee plants. But there are many serious difficulties in the way of its application on 

 a sufficiently large scale. Some of these difficulties I note below for your considera- 

 tion. The large size of plantations, varying from 200 to 1,000 acres, which, at the 

 average rate of 1,500 trees per acre, gives from 30,000 to 1,500,000 individual trees to 

 be treated on a single plantation. These plantations are situated on steep hill-sides, 

 intersected only by narrow and rough foot-paths ; consequently the liquid and appa- 

 ratus would have to be transported entirely by hand labor. Unless this treatment 

 were simultaneously undertaken by every planter, the infection would be continually 

 re-imported. And even if united action could be made compulsory it would still be 

 impossible to disinfect the indigenous trees and plants which at present act as reser- 

 voirs of the pest. I fear that the expenditure necessary to meet all these difficulties 

 would be quite prohibitive. But if you still consider otherwise, and would kindly 

 give me an idea of the probable cost of apparatus (or refer me to a manufacturer of the 

 special nozzles and force-pumps used in this work), I would estimate the cost of the 

 treatment and lay the plan before our Planters' Association. — [E. Ernest Green, Eton, 

 Punduloya, Ceylon, June I, 1889. 



Reply.— * ** * The fact that the crop is grown upon hill-sides and that the 

 field is only intersected by narrow foot-paths would render one of the knapsack pumps 

 the only one which could be used for this purpose. European manufacturers have 

 placed upon the market a number of desirable knapsack pumps, some of them hold- 

 ing several gallons, and all of them fitted with some modification of the Riley nozzle, 

 which insures a fine spray and an economical distribution of the liquid. Knowing so 

 little about the value of the crop and the amount of damage which the scale insects 

 really cause, I can not pass judgment upon the advisability of the introduction of this 

 remedy extensively, but I should surely say that it would pay to import one of the 

 Verm orel pumps complete and make some careful experiments by its use with a good 

 emulsion. * * * [July 3, 1889.] 



A new Quince Enemy. 



I inclose herewith a match-box containing Quince leaves infested with insects. 

 The Quince tree is in a garden among pears, peaches, plums, pomegranates, figs, grapes, 

 apples, etc. This is the second year that the Quince has been infested, and to such 

 an extent as to check its growth and render it un.ruitful, but I can discern the in- 

 sects on no other tree. I should be glad to know the name of the pest and how to 

 destroy it.- — [W. Jennings, Thomasville, Ga., June 24, 1889. 



Reply. — Your letter of June 24 and the accompanying specimens of the insects 

 found upon the leaves of your Quince tree have been received. The insect is one which 

 has no distinctive common name. It feeds upon a variety of plants and is usually called, 

 when found upon any particular one, by the name of the plant ; as, when found upon 

 hawthorn, it is called the "Hawthorn Tingis," when found upon butternut it is called 

 the " Butternut Tingis." Its scientific name is Corythuca arcuata. It has cot previ- 

 ously been recorded upon quince so far as I know, and this habit will enable it to do 

 considerable damage when occurring in great numbers. If you will spray your trees 

 with a dilute emulsion of kerosene and soap you will be able to destroy the insects 

 which are now present, and if you will burn the rubbish under the tree in the fall 

 instead of making a mulch around the base you will probably lessen the appearance 

 next season. * * *— [June 28, 1889.] 





