Fig. 17. 



78 



Vanessa and Grai^ta sp. are sometimes very abundant, and are collected and destroyed 

 as soon as discovered. Cecropia and Eacles are always abundant and on many of the 

 smaller trees do much damage. These are hand-picked and destroyed. 



Alypia octomaculata (Fig. 17) is one of our most troublesome caterpillars, the great 



abundance of Ampelopsis vines in the parks, and especi- 

 ally around it, covering " squatter sovereignty " houses, 

 affords congenial food for its rapid propagation. In the 

 parks the vines are twice annually treated with a solution 

 of London purple, applied with a spraying machine. This 

 is found most effective and the vines do not seem to be 

 injured as easily as most plants by the arsenites. 



The Elm Beetle, Galeruca xanthomelcena, has given us 



an immense amount of trouble, and many thousand trees 



have been sprayed each year for their destruction, and 



with good effect. The means we have adopted during 



the past three years is rather more in the preventive 



line. As soon as the tirst eggs are found that part of the 



tree is at once sprayed. I am inclined to think the Elm 



Beetle is double-brooded with us. 



The Elm Borer, Zeuzera pi/rina^ is getting to be very destructive with us, already 

 twelve species of trees and shrubs are affected by it, and during the past year two men 

 were kept during May at collecting the larvae from broken branches. All branches as soon 

 as detected in a weak or broken state are removed and the larvae extracted. In very 

 choice trees the limbs are carefully examined and where holes can be found bisulphuret 

 of carbon is put in with an oil can and putty put over the hole. This is only resorted to 

 in the case of rare trees and shrubs. 



For scale insects the trees are washed with preparations and then cleaned with steel 

 brushes, leaving all in fine condition. Many thousand trees and shrubs have in this way 

 been put in fair condition. 



A large number of poisons have been experimented with for Aphis and other insects, 

 due notice of which will be given in reports soon to be published. 



The spraying machine used by the department of public parks is a two-barrel 

 machine manufactured by the Nixon Nozzle Company, Nixon, Illinois. This machine, 

 to better adapt it for city work, has been entirely remodelled. A set of strong cab-wheels, 

 with a strong axle, was first made, then a pair of stron g easy springs, so as to make the 

 tank less liable to jars. The tank was lined with zinc entire, and on top of the tank was 

 placed a well about a foot high to keep the liquid from flushing over. Un the rear of the 

 tank was placed a box for poisons, hose, etc., and o-n the. front a box for ccats, lunches, 

 and collecting cases and bottles. On one side of the machine and running' nearly to the 

 horse's breast was placed the bamboo pole used to elevate the h. ose and on '.the other side 

 long handled pruning shears. Thus equipped the men drive a'll over the city and are at 

 any time or place ready for work at short notice. 



Our parks comprehend nearly 4,000 acres, and are from one extreme to the other 

 sixteen miles apart. The work with the present force and appliances is chiefly 

 centred in the island parks and places. 



SOME HISTORIC NOTES. 



BY A. J. COOK, AGRICULTURAL COLLEGE, MICHIGAN. 



Upon special request, T am very pleased to state the following facts regarding the 

 early use of the kerosene emulsion and of the arsenites. 



I used kerosene and soap mixture, as I then called it, successfully in 1877. I used 

 very nearly the same proportions that I prefer now, heated it to dissolve the soap, and I 



