December i, 1884.] THE TROPICAL AGRICULTURIST. 



45« 



attained some size and carry several leaves but as the in- 

 sects increase in size, these tips again are attacked, 

 and other shoots start from other eyes, though attain- 

 ing a less vigorous growth, and in a short time we 

 have a ' broom ' where not one leaf or tip has been 

 taken by us, but has been killed off or sucked dry 

 by the bug alone : drawings of such I scud herewith to 

 illustrate. When this is the case, growth will have come to 

 a complete standstill, ascvcry shoot require s from (say) forty 

 to fifty days to mature from an eye to be fit to pluck. We 

 may Bay the trees shut up for about twocntiro mouths at least, 

 and is specially unfortunate that this takes place usually 

 about mid-season, and when we should he doing our very 

 best. I do uotstatcthat the entire garden is thus affected 

 at onco, or wo should soon see tea itself at a standstill, 

 but the particular patches and trees most blighted are so 

 as before stated. It is difficult to tell what part will 

 be attacked this year or next: all places seem pretty 

 equally liable to blight, and, unless very bad indeed, it 

 is seldom seen, as yet, over an entire garden at once; 

 but that this will be the normal state eventually I do 

 not doubt. The recovery of the tree is slow, unless 

 pruned, and this is about ns bad as the disease, as far 

 as our outturn of crop is concerned." 

 And now Mr. Wood-Mason describes his important 

 discovery of the mode in which the creature deposits 

 its eggs, a knowledge < f which ought to give planters 

 of the present day a great advantage : — 



It was reserved for me to dicover the manner and 

 position in which the tea-bug lays its eggs ; and a brief 

 but sufficient account of my obseravtious is given in the 

 following communication addressed by me on June 8th, 

 18S1, to the Chief Commissioner of Assam, by whose 

 orders it was published in the Assam Gazette for general 

 information : — 



" Tea-Bug. — Have discovered, by observation of speci- 

 mens of this formidable pest kept in confinement, that 

 the female deposits her eggs singly in the substance of 

 the tenderest shoots of the plant, in the internodes or 

 portions of the stem between the pekoe aud the two or 

 three leaves succeeding from above downwards, and in 

 the buds developed in the exils of plucked leaves and in 

 the parts thereabout ; that tho preseuce and position of 

 oach egg is from the first indicated on the exterior by 

 two unequally long, glistening, white, bristle-like prolong- 

 ations of its shell, and later by discoloration of the point 

 pierced. Have discovered by dissection that she is pro- 

 vided with a serrated ovipositor, of the shape and sharp- 

 ness of a sabre, wherewith to pierce holes in the 

 soft tissues of the plant for the reception of 

 her eggs. These observations have been verified hi 

 the field upon numerous blighted hushes ; hut. 

 though eggs have readily been found by the unaided eye on 

 blighted portions of bushes, not a single one has yet been 

 seen on any perfectly uninjured shoot. The vigorous and 

 unremitting plucking of the blighted portions of bushes 

 might mitigate the evil; and I would suggest that this 

 message be sent to newspapers and published in the Gazette, 

 for general information." 



The agents and owners of tea-estates had always attached 

 the greatest importance to the discovery of the eggs, as 

 they booed by the destruction of these to effect the exter 

 min ation .if the pest, or at least a diminution of its numbers 

 and with the view of assisting the planters in finding out 

 in what part of the plant the eggs were deposited, long before 

 I' visited Assam, I had suggested that eggs or viviparously 

 produced young should be sought on the young and tender 

 shoots. Some time before my mission was arranged, I 

 received from Mr. Alexander Wilson several microscopic 

 slides, which that gentleman informed me, were supposed 

 to contain viviparously produced young taken fromiouug 

 shoots by one of his employes, who, I think it was stated, 

 had actually witnessed their birth on the shoots. 



These sliiles proved on examination to contain ripe 

 which had evidently been taken from the bodies 

 of f -in: 1 'S and not from the plants at all — the preparer 

 of them having evidently mistaken the two unequal 

 process! s which spring from the mouth of each 

 egg for antennae, and hence jumped to the conclusion 

 that he had found f ally-formed embryos ready to be de- 

 ! i the Kiisjir.. Though 1 never succeeded 



in finding embryos in eggs extracted from the bodies of 



females, it is possible, but highly improbable, that under 

 certain circumstances such may occur, that eggs may be 

 retained by the females until development so far advanced, 

 aud he inserted in this condition in tho usual manner into 

 the substance of young shoots just as undeveloped eggs are. 

 The knobbed ends and also the sides of the two tubular 

 processes of the mouth of the egg-shell, to a greater or less 

 extent, are studded with button-shaped elevations, each of 

 which has a minute pit.m its centre. These pits are prob- 

 ably the endsof minute tubules which plan' tho lumens 

 of the processes in direct eonimuuication with the exterior, 

 and thus serve to carry air to the developing ovum. The 

 eggs are provided with' deep saucer-Shaped lids, perforated, 

 sieve-like, with holes which are large enough to admit sperm- 

 atozoa. 



I placed four or five virgin females in company with 

 males, in a i age with fresh tea shoots. I witnessed the union 

 of the sexes, and the subsequent deposition of the eggs. 

 As soon as the eggs were laid, I dissected one of them 

 out of the shoot, and mounted it in glycerine and water. 

 On crushing the preparation by slight pressure of tho 

 coveriug glass, the contents of the unsegmented ovum ran 

 out together with four spermatozoa. I still possess this 

 preparation, which is proved to have been made from an 

 egg taken from a shoot, by the presence of masses of the 

 tissues of the plant containing spiral vessels. The respir- 

 atory processes of the egg shell so closely resemble the fine 

 pubescence which clothes the surface of the shoots as to 

 be quite indistinguishable from it to the unaided eye, 

 to eyes unaccustomed to zoological work, even with the 

 aid of an ordinary lens; so that it is no wonder that the 

 planters had altogether failed to find the eggs of this 

 pest, after these had left the bodies of the females. 



In order that the render may form some idea of the 

 numbers of the eggs, I may state that on one occasion 

 I conuted more than forty eggs in twelve shoots taken 

 consecutively and a'; random, from a plueker's basket, and 

 that on another occasion I selected and plucked from one 

 bush of a plot of tea, which was only moderately blighted, 

 four shoots with one or more eggs in each. The females 

 appear instinctively to avoid puncturing the shoots or the 

 parts of the shoots in which they lay their eggs, for one 

 can rarely find eggs ou badly injured shoots. 



Each of these pests stands to the plant in the relation 

 of parasite to host, and the plants effected may be con- 

 sidered to be suffering from parasitic disease. 



After an exhaustive examination of every case, in which 

 the quality of the soil, or shade or "want id' cultiv- 

 ation," aud the bug-disease seemed to be connected 

 as cause and effect, I have arrived at the conclusion 

 that neither of these separately, nor all three in 

 combination, can be considered to be the cause of, al- 

 lium ;h they may when combined possibly promote, the 

 disease. 



Many animils are protected from the attacks of their 

 enemies by their nauseous flavour or odours, or by both, 

 and their enemies recognize them by their odour, or, in 

 default of this, and after experience of their flavour, by 

 their colours, and hence avoid them. Why should there 

 not he similar protective odours and flavours in plants r 

 Mr Wood-Mason then goes on to indulge in specul- 

 ations, atwhich we suspect most planters will smile, to the 

 effect that the tea bug chiefly affects China bushes, be- 

 cause of the mild flavour of this kind, while they are de- 

 terred from attacking the indigenous Assam because 

 of the "rax/ling" flavour of the infusion yielded by 

 its leaves ! In all our reading of the literature of 

 Indian tea, we certainly never understood that pure 

 ndigenous Assam tea Mas more exempt from the 

 " I light" than China bushes, but Mr. Wood- Mason's 

 very positive assertion, if it can be substantiated', 

 peserves special attention. He writes : — 



The species which affords the strong and rasping liquor 

 when pure, enjoys an almost complete immunity from at- 

 tack ; but the species which affords the milder liquor 

 suffers most severely. I havo no doubt that tho more 

 powerful juices of the indigenous tree serve* to protect 

 it From its enemies, and that the milder juice of the 

 Chinese hush render it. liable to attack. The question 

 arises, how do the bugs distinguish between the two? 

 l'.y their olfactory organs just as other insects distinguish 



