88 



size and abundance, was the nine-spotted lady bag ( Goccinella 9-notata). It 

 may be recognized by the arrangement of the nine black spots on the brown 

 wing covers — four on each side, the ninth just behind the thorax and overlying 

 the middle line. It is very nearly a half sphere in shape. The other species are 

 like it in general shape, but differ in details of colour and markings. A small list 

 of other insects which do more or less good in destroying the aphides could be 

 given, but this will suffice to give an idea of the more abundant and useful of our 

 insect friends. 



Birds have been thought to destroy the lice, but 1 have seen no evidence of 

 their doing so. Most birds depend on larger insects, and it is only occasionally 

 that the small species, such as warblers, eat plant lice of any kind. Excepting 

 the Maryland yellow-throat, birds of this family rarely occur in our grain fields, 

 so that we can hope nothing from their help. The English sparrow, with its 

 clumsy beak and grain-eating propensity, certainly does no good in this direction. 



Experiments with Arsenites. — In the Bulletin of the Iowa Agricultural 

 Experiment Station for August, 1890, Prof. Gillette gives an elaborate and inter- 

 esting account of a series of experiments that he carried out for the purpose of 

 testing the use of aisenites in the warfare against noxious insects. 



"Paris green, he says, was brought into prominence as an insecticide for the 

 first time in this country in 1869, and London purple in 1877. Arsenious acid 

 (white arsenic) was successfully used for the destruction of the Canker-worm as 

 early as 1875 and is still frequently recommended for the destruction of insects. 

 During these years the arsenites have arisen to the first rank as insect destroyers. 

 They have been largely experimented with by entomologists and widely used by 

 farmers and fruit-growers, and yet there is much difference of opinion as to the 

 proportions in which each may by safely applied to different plants for the des- 

 truction of insects. In fact a serious obstacle in the way of a more free and 

 successful use of the arsenites has been their liability to injure tender foliage, 

 even when applied very dilute. In the experiments of the past two seasons, 

 herein reported, I have given much attention to the finding of some method of 

 applying these poisons so as to prevent injury to foliage without lessening their 

 effectiveness in destroying insect life, and the success met with in this direction 

 has been most gratifying. I also give the results of experiments to determine rela- 

 tive injuries to foliage from applications of the arsenites when freshly mixed and 

 when allowed to stand a few days before being applied; to show the effect upon foli- 

 age by adding paste or soap to arsenical mixtures ; to show the effects of sun, dew 

 and rain upon foliage treated with arsenical mixtures ; to show whether or not 

 it is practical and safe, so far as injurj^ to the plant is concerned, to mix the ar- 

 senites with insecticides that kill by external contact ; and to show the effects of 

 combining the arsenites with fungicides." 



After giving a detailed account of his various experiments, he arrives at the 

 following conclusions : — 



" 1. The oldest leaves are most susceptible to injury from arsenical applica- 

 tions. They often turn yellow and drop without showing the burnt spotted 

 appearance* 



2. Dews, amd probably direct sunlight, increase the injuries done by the 

 arsenites to foliage. 



* I have put in italics those conclusions that seem to me to be well proven from the experiments here 

 reported. Concerning the others there is some doubt, and further experiments are necessary to determine 

 positively the facts. 



