42 



THE AGRICULTURAL NEWS. 



Febeuary 11, 1905. 



INSECT NOTES. 



Coflfee Scale Insect. 



Dr. H. A. Alford Nicholls, C.M.G., of Dominica, 

 recently sent to the Head Office of the Imperial Department 

 of Agriculture some leave.s of Liberian coffee attacked by 

 a scale insect which he says is new to his experience. 



Examination shows it to be Lecaniuiii viride, known in 

 Ceylon as the Green Bug of coffee. Mrs. Fernald, in her 

 Corcidae of the World, records this insect from Ceylon, 

 Mauritius, and Brazil, and it has been sent to this office 

 from Egypt. Its native country is not, however, known. 

 Mr. E. E. Green, Government Entomologist of Ceylon, 

 considers that it has been introduced into tliat country. 



Dr. Nicholls reports that ' it appeared some months ago 

 on abandoned Liberian coffee trees at St. Aroment and it 

 spread to lime trees in the vicinity. I have kept it in check 

 by spraying with kerosene oil enmlsion which is fatal to the 

 insect in its younger and more tender stages.' 



A sharp watch should be kept on this insect and vigor- 

 ous measures taken to suppress it on its first appearance 

 on lime, cacao, or coffee estates. 



Directions for Preserving Gall Material. 



Dr. A. Nalepa, of Vienna, who is an authority on 

 the eriophyoid mites, writes that dried gall material is 

 generally unfit for careful stud}'-, as is also alcoholic 

 material. The following directions for the preservation 

 of gall material and mites, are taken from Dr. Nalepa's 

 letter : — 



A portion of each kind of infested plant should be 

 preserved in weak spirit and a portion dried for the gall 

 herbarium. The mites for careful study are got out of the 

 galls in this manner : — The mite-infested material is cut into 

 small pieces, 1 mm. to 3 mm. wide, and placed in a tall 

 glass cylinder, wrapped with paper to keep out the light, 

 and left to dry. The mites will crawl out of the galls, and 

 after eight to twelve hours acid alcohol (3—5 drops of 

 hydrochloric acid to 100 c.c. of 50 i)er cent, alcohol) is 

 poured in, and the whole well shaken. The alcohol is poured 

 through a sieve into a beaker, and the gall material returned 

 to the cylinder for a second washing. Fresh alcohol should 

 be used each tune. The alcohol is allowed to stand till all 

 the sediment is at the bottom of the beaker ; the alcohol is 

 poured off, and the sediment containing the gall mites is 

 saved in a small vial in about 00 per cent, spirit, and care- 

 fully labelled. 



Hardbacks. 



The following notes on the strength of the common 

 hardbacks {Lujyria tutindosm) may be of interest. This 

 common insect is a ground beetle, the larva lies under 

 ground feeding on roots and other vegetable matter. 

 After emerging from the pupa case, it is supposed that the 

 adult beetle forces its way to tlie surface. To do this 

 considerable strength is required. The three exi)erinients 

 given here show that the hardback possesses great strength, 



althou'^'Ii it is by no means certain that these figures re[ire- 

 sent the limit of its strength. 



(1) A hardback was harnessed with a piece of thread to 

 a small card. The thread passed over the thorax between 

 first and second pairs of legs and under the body. The 

 beetle and its card drag were placed on coarse card board. 

 AVeic'lits were placed on the drag to the amount of 4'09 

 grammes. The beetle weighed -265 grammes. 



(2) A hardback was placed under an inverted glass dish 

 54 mm. in diameter, and 13 mm. deep. In this case the 

 beetle crowded against the side of the dish and getting 

 firmly braced raised head and jirothorax to start the load, 

 then "walked along pushing the dish. Weights were placed 

 on the dish amounting to 20 grammes which with the 

 weight of dish, 17't grammes, made a load of 37'4 grammes. 

 This beetle weighed '265 grammes, and the test was made 

 on fine blotting paper. 



(3) The same beetle was used under a small metal box 

 with a glass top. The box was 39 mm. in diameter and 

 6 nun. deep. The beetle's body was 7 mm. thick so that 

 tlie top of the box rested on its back and only a portion of 

 the edge of the box rested on the blotter on which the test 

 was made. The weight of the Ijox was 6'25 grammes, and 

 100 grammes weight was placed on it, making a weight of 

 lOG-25 granunes. 



In the first experiment the proportion of weight of insect 

 to weight of load was '265 gr. to 4-09 gr., or 1 to 15-43. In 

 the .second, -265 gr. to 37-4 gr., or 1 to 141-1. In the third, 

 3-05 gr. to 106- 25 gr., or 1 to 400. 



The extraordinary strength of these little animals will 

 be better realized when it is stated that, under similar 

 conditions to those existing in the first two experiments, 

 a man would be able to draw only 86 per cent, of his total 

 weight and a horse 67 per cent. It should be mentioned 

 that in the third experiment a part of the weight is carried 

 and a part jiushed. 



LECTURES IN ECONOMIC BOTANY. 



The following. i.s the syllabus of a course of lectures 

 ' On recent investigations in Economic Botany' which 

 were to be delivered, under the auspices of the Univer- 

 sity of London, at the Chelsea Physic Garden on 

 Fridays, during the Michaelmas Term, 1904, bj' 

 Mr. W. G. Freeman, B.Sc, A.R.C.S., Superintendent of 

 the Colonial Collections of the Imperial Institute : — 

 Lecture I. (November 11, 4.30 p.m.). 



General. — Scope of Economic Botany. Working 

 organization. Past results. Present-day questions. 

 ^uriar-j^roducing plants. — Sugar-cane. Cultivation 

 and manufacture of sugar. 

 Lecture II. (November 18, 4.30 p.m.). 



Sugar-cane. Imi)rovement. Bud variation. Chem- 

 ical selection. Seminal variation. 

 Lecture III. (November 25, 4.30 p.m.). 



Sugar-cane. Importance of factors other than 

 sugar content. Disease resistance. 

 Lecture IV. (December 2, 4.30 p.m.). 



Sugar-beet. — Summary of past work. Imi)rove- 

 ment effected by seed .selection. Composition a.s 

 affected by environment. General summary of 

 sugar production. 

 Lecture V. (December 9, 4.30 p.m.). 



Cotton. — Source. Other vegetable cottons. Improve- 

 ment of cotton. 

 Lecture VI. (December 16, 4.30 p.m.). 



Improvement of cereals, especially of Indian corn. 



