76 
The Streaked Cottonwood beetle (Plagiodera scripta) appeared in our 
grounds during June on a young Populus, which it threatened to ecom- 
pletely defoliate. The tree being small admitted of thorough drenching 
with a plant syringe with the solution of arsenic and ammonia—1 ounce 
of arsenic in 1 quart of aqua ammonia—i tablespoonful of the solution 
to a gallon of water, by which means and a little hand-picking the pest 
was so thoroughly exterminated that it did not reappear later in the 
season. 
The 12-spotted Diabrotica (D. 12-punetata) was a serious pest during 
the latter part of the season, not only on squash and cucumber vines, 
but on late sweet-corn, and especially in its injuries in the flower garden 
on the blossoms of roses, dahlias, and cosmos on which it literally 
swarmed. To save the flowers it was necessary to make the rounds two 
or three times a day and capture or put the beetles to flight. They 
were not much affected by any of the milder insecticides, and the arseni- 
cal remedies could not very conveniently be applied. 
The European Cabbage-butterfly (Pieris rapa) acquires one or more 
new food plants annually and threatens to become quite omnivorous. 
This year it proved in several localities very destructive to nasturtiums 
(Tropewolum) both in flower and vegetable gardens. None of its para- 
sites have yet appeared, so far as I have been able to ascertain. It 
seems to have entirely supplanted our native P. protodice in this locality. 
Wishing to obtain some larvee of the latter for a certain purpose, I made 
many examinations during the summer of the neigbboring cabbage 
plantations, but did not succeed in finding a single one. 
SPECIAL STUDIES. 
Tue SPINACH BEETLE. 
(Disonyehe collaris Fabr.) 
About the middle of April I observed the leaves of spinach in the gar- 
den were badly perforated, and, upon examination, I found on the un- 
der surfaces numbers of small, dingy, white larvie, evidently of some 
Chrysomelid beetle. They reposed in the numerous depressions between 
the veins, and a slight shake or jar caused them to drop to the ground. 
The insects increased in size and numbers until by the middle of May 
all the leaves were badly injured and the gardeners hereabout com- 
plained that their spinach was so *“‘ worm eaten” this year that they 
could no longer offer it for sale. A few of the samelarve were also found 
on young beet leaves, especially of the white and yellow varieties, and 
upon the wild Chenopodium album, the latter being, I suspect, the orig- 
inal food plant of the insect. 
As the larvie drop so quickly upon being disturbed, it is not often 
that they are observed by the gardener or cook, and the damage was - 
attributed by many to “some kind of cut-worm.” By_ plucking the 
é ome 
