Mai-di 28, 1873. ] 



JOUENAL OF HOETICULTUEE AND COTTAGE GARDENEE. 



271 



The four mugs are transparent and brownish in colour, the 

 head and thorax black, the antenuse yellow, and also the abdo- 

 men, which is banded with blacls. The female has an auger, 

 furnished with powerful muscles, by means of which the eggs 

 are introduced into the solid wood of trees. This species 

 seems widely distributed, and has been found at Chelsea, in 

 Kensington Gardens, and other places near the metropolis. 

 Though strong in flight, however, it rarely seems to travel very 

 far from the Firs within which it has been reared to maturity. 

 The perfect insect is more common some years than others. 



Sires gigas. 



and the reason of this is assumed to be that the larvae grows 

 slowly, being, in fact, either two or three years in reaching its 

 full proportions. These creatures are fleshy and cylindrical ; 

 the head is homy, and there is also a horny point at the anal 

 extremity of the body. The feet, of which there are six, are so 

 minute as to be scarcely noticeable when not in use. Various 

 stories have been pubUshed from time to time about the emerg- 

 ence of these flies from wood which had not only been felled 

 some time, but actually worked-up into floorings and rafters. 



Another Sirex by no means rare in Britain is S. juvencus ; 

 and this is less in size than the preceding, though different 

 individuals vary much. Apparently this is due to the peculi- 

 arities of the food in the larval state ; it is not a distinction 

 between the sexes. The female of this species may be known 

 at once by her steel-blue body and yellow hind legs. The 

 male has black hind legs and a jellow body. According to 

 Mr. Newjuan there are three varieties, each of which keeps to 

 a particular species of Fir. He states their differences thus : — 

 " The first, Laricis, has black antenuic, and a black tip to the 

 abdomen in the male ; the larva feeds on Pinus Larix. Se- 

 condly, Sylvestris has also black antenna", but the male is 

 without the black tip to the abdomen, which is entirely yellow ; 

 the larva is found in the wood of V, sylvestris. The third 

 form is named Abietis, with antenna) black at the tip and 

 yellow at the base ; the larva feeds on the wood of P. Abies." 

 -Vs the first and last of these trees are not considered natives 

 of Britain, Mr. Newman considers that the special form of the 

 insect which attacks them may have been mtroduced as well. 



One of the most smgular circumstances in the history of 

 these insects is this, which is well authenticated, that the flies, 

 when they have emerged in confinement, have attacked metal 

 with theh mandibles. Some perforations were first observed 

 in balls sent to the Crimea m 1856. M. Dumeril rather hastUy 

 assumed that these were made by the weapon with which the 

 females are armed, and which serves as an ovipositor. The 

 destruction of some cartridge cases in 1861 was brought under 

 the observation of M. Bouteille, who found that both sexes of 

 S. gigas had been at work. The boxes containing the car- 

 tridges were made of fir wood, and the insects enclosed at first 

 as larviE became pupae and then imagos, and, bemg unable to 

 liberate themselves, bored through the paper wrappings and 

 the powder, and even tried their mandibles, not unsuccessfully, 

 upon the solid lead. A similar faculty has been attributed to 

 the larvHj, and it is quite possible that this is correct, since the 

 lai'vie of some beetle and those of the well-known Goat Moth 

 have been known to make perforations in lead and other soft 

 metals. 



Various Aphides and Cocci resort to Conifers, often in con- 

 siderable numbers ; and that elegant and favourite tree, the 

 Larch, is especially persecuted by one of the latter species, 

 ordinarily designated as the Scale, and also the Larch Blight, 

 and which was supposed by Kirby and others to be of the 

 l'l:i"i li- ■ fiiiiiily. This species, Eriosoma Laricis, hardly ever 

 |Mr ,;iil . ;t (o kill thc trcc, but it gives to the Larch a very 

 di j'l^ r.il'lr aspect. It is stated that in a spring season like 

 that \\ hich is probably coming upon us this Coccus is peculiarly 

 troublesome. The mild weather in January and February 

 hastens the development of the insect broocl; and the tree, 

 especially if young, has (luite enough to do to hold its own 

 against the unpropitious weather so freijueutly ensuuig in 

 March and April, without being bothered by so pertinacious an 

 insect enemy. Frost, fog, and cold winds, too, which are 

 unfavourable to vegetable life, do not trouble the Cocci much, 

 if at all. One cause of their comparative immunity is the 

 cottony exudation from their bodies, which not only furnishes 

 a protection against cold and moisture, but helps to divert the 

 attacks of other animals which would make them their prey. 

 As summer advances the insects spread themselves abroad, 

 and the Larches which are infested become clammy and dark 

 with the excretions of the Cocci, which are half-saccharine 

 half-resinous, and which liave a fascinating effect upon ants, 

 similar to that produced by the honeydew emitted by the Aphis 

 tribes. Through all the stages of their existence these little 

 creatures are active, employuig the rostrum, or sucking appa- 

 ratus, mth which they are furnished to draw from the tree or 

 plant the sap which is so essential to its health. Only towards 

 the close of their lives, when they have deposited their eggs, 

 do the females become torpid ; the males, however, which are 

 developed towai'ds the end of summer, take wing, and may be 

 occasionally seen in swarms about the plantations. I do not 

 think, however, that they migrate from one locality to another 

 at a distance. During the winter months the eggs of the 

 Coccus may be seen with the naked eye, or still more plainly 

 by means of a hand-magnifier. They are most frequently 

 situated about the buds and in the crevices of the bark, 

 appearing as black grams. Perhaps these might be dealt 

 with successfully in some cases by washing them from 

 young trees by means of warm water, though it would 

 scarcely kill the germ in the egg. It has been found, how- 

 ever, that water of 120° destroys the living Cocci, and, ap- 

 plied by syringing, it is of great service, no harm being done 

 to the Larch thereby, unless the temperature of the au- is very 

 low at the time. 



The Silver Fir has its scale insect, and this has a singular 

 hal-iit. lUilike most Aphides and Cocci, it does not infest the 

 leaves iif tlir tvpr, its favourite haliitiit is the trunk and the 

 uiiilrr sid'' Mf lli^' iM.nirhi'K. In cnt.iiii instances this Coccus is 

 so jirelilii- :ind [iri t iniHii.ii in ii , ;itt;ii-Ivs a, to cause the death 

 of the tree, or to force il niLo, instead of the usual growth, an 

 unhealthy yellow fohage ; at last, the tree becomes, as it were, 

 encrusted with a mass of living matter, which is hidden from 

 a first inspection by a coating of white and mealy-looking 

 substance. Owing to this natural protection various remedial 

 applications, such as limewater and infusion of tobacco, which 

 would be fatal if applied to the body of the Coccus, fail to do 

 much good. On very choice trees a careful scrubbing of the 

 parts infected with a suitable brush or with wisps of hay has 

 been tried, and found to answer well, the objection being the 

 time and labour required. 



The species which commonly bears the name of the Mealy 

 Bug (Coccus Adonidum) is remarkable, 

 because it frequents the Vine, as well 

 as different species of the genus Pinus. 

 The males are so small, and so seldom 

 seen, that some persons have come to 

 the conclusion that there are none ; 

 but though the females are to some 

 ext'.nt capable of producing progeny 

 without the intervention of the males, 

 this cannot be continued beyond a 

 limited number of generations. 



One writer on gardening commends 

 the following compound as a destroyer 

 of this and others of the Coccidte : — 

 •2 lbs. of sulphur and 2 lbs. of soft 

 soap are worked on into a lather with 

 warm water, and two or three fluid 

 ounces of spirit of turpentine. A de- 

 coction of tobacco is made by boiling a pound of it in two or 



Coccus Adouiduni. 



