405 



would also answer if liglits were placed before or ou boards painted witli 

 a thick sirup, or any adhesive substance like the celebrated fly-paper. 

 In the*former part of this article, it was mentioned that the common 

 name of thrips is misapplied when used to designate the grape-leaf hop- 

 per, the true thrips being a very different insect and belonging to an 

 entirely different family. The true thrips is very minute in size, and 

 lias a long and slender body; the wings are long, narrow, and 

 fringed with fine hairs; they live on leaves, flowers, buds, and 

 also infest grape-leaves. And although almost all European 

 authorities are unanimous in saying that they are injurious to 

 grains, foliage, «S:c., Mr. Walsh states that although hitherto 

 considered as vegetable-feeders, they are generally, if not universally, 

 insectivorous, and feed on the eggs of the wheat-midge arid other 

 insects. Mr. Eiley also states that a species of thrips destroys the 

 eggs of the curculio. Notwithstanding these proofs of the "cannibal" 

 propensities of the true thrips, we are also convinced that it causes 

 injury to several kinds of plants by draining the sap from them ; as some 

 grape-leaves, infested by the. true thrips, and with no other insect on 

 them whatever, when subjected to examination under a powerful micro- 

 scope were found to have the sap exuding in minute drops or globules 

 from numerous small punctures or holes made in the leaves, and which 

 had evidently been made by the 'thrips, as some of these insects were 

 actually employed in boring the leaves at the time, and no eggs or any 

 other insects could be discovered. It is true the thrips may possibly 

 destroy the eggs of the vine-hopper, and of other insects also, but no 

 doubt they also injure foliage by draining them of sap. This fact may 

 be more jilainly demonstrated by examining the plants in any green house 

 infested with the true thrips, where there are no vine-hoppers whatever, 

 and the thrips-infested plants may readily be recognized by their spot- 

 ted and unhealthy appearance. Some of the same remedies already 

 proposed for the destruction of the vine-hoppers, as syringing with soap- 

 suds, &c., would j)robably alsc^ answer, if applied, to destroy the true 

 thrips. 



SCIENTIFIC NOTES. 



YOELCKER ON soiLS.-^Mr. Voelcker, an eminent agricultural chemist, 

 lately delivered a lecture before the Chemical Society of London upon 

 the productive power of soils in relation to the loss of plant-food by 

 drainage, in which he took occasion to refer to the inutility, for most pur- 

 poses, of the analysis of soils, as ordinarily conducted. He states that 

 there are many apparently similar soils — that is, soils in which analysis 

 shows like quantities of the same constituents — which differ widely 

 in their productive powers, owing to the fact that the indications are of 

 ultimate comi^osition instead of showing states of combination in which 

 the ingredients exist in the soil. 



Another consideration of importance is that soil analyses throw no 

 Hght upon the physical or mechanical conditions which affect the fertility 

 of land. The productiveness of land is much influenced, too, by the 

 character of the sub-soil and its composition in I'elation to the surface- 

 soil, of which a soil analysis conveys no information. Again, meteoro- 

 logical conditions, such as the aspect of the field, the prevailing wind, 

 the amount of rain, and the distribution of the rain-fall in the year, are 



