62 
violent struggling evidently assisted in the breaking of the larval skin, 
leaving the pupa bare. This transformation from larva to pupa is 
hardly as interesting as the rapid development of adults, 18 of which 
issued within fifteen hours after transformation to pupa, whereas 
previously the shortest duration of the pupal state which we had 
observed was forty-eight hours. It looks like an effort of nature to 
perpetuate the species in the presence of a unique emergency. 
On the whole, the result of the experiments with tar and tar oils was 
rather unsatisfactory as compared with the heavier grades of kerosene. 
The effect of the tar was not permanent, and the effect of the creosote 
oils was not as rapid as that of kerosene, and the writer is inclined to 
the opinion that the heavier grades of kerosene oils are, on the whole, 
preferable, although the effect of the creosote oils is very good, and 
they can be used to advantage. He is inclined to think that they may 
prove to be more permanent, although not quite so rapid in their 
effect, than the lighter illuminating oils. 
EUCALYPTUS TREES. 
In addition to the use of eucalyptus oil on the skin to keep mosquitoes. 
from biting, the growth of eucalyptus trees is said by certain persons 
to drive mosquitoes away, and trees of the genus Eucalyptus have 
been especially recommended for planting in malarial regions. Mr. 
Alvah A. Eaton, of California, wrote us in 1893 that in portions of 
California where the blue gum occurs no other remedy need be sought 
for. Further than that, he stated that no matter how plentiful the mos- 
quitoes, a few twigs or leaves laid on the pillow at night would secure 
perfect immunity. The same year Mr. W. A. Sanders, of California, 
sent the following interesting account of the value of eucalyptus trees 
in answer to our published request in Insect Life: 
I have the largest and oldest grove of trees of Eucalyptus globulus in this part of 
California, and have had fifteen years of opportunity to study these trees as insect 
repelHants, and deem it my duty to respond to your request on page 268 of Insect 
Life. 
Thirty-three years ago I spent a portion of one summer with a Dr. McConnell, who 
had just returned from some years of residence among the Eucalyptus forests of Aus- 
tralia. We were in the Sequoia (Sequoia sempervirens) forest of the coast region of 
our State. The mosquitoes were so bad that it was nearly impossible to work during 
days when there was no wind. The doctor assured me that our common mosquito 
was never found in the Australian Eucalyptus forests and swamps, but added, There’s 
a “spotted mosquito” nearly as bad there in some places. He, not being an entomolo- 
gist, was unable to tell me whether the ‘‘spotted mosquito’? was a species of the 
genus Culex, or of some allied genus. 
The doctor being a reliable, close observer, I determined to test the antimosquito 
qualities of the Eucalyptus; so when I began to improve my house here nineteen 
years ago, one of the first things I did was to get a lot of eucalyptus seed from Aus- 
tralia and plant out a grove oi the trees. The tallest of them are now over 140 feet 
tall, and can be seen for 20 miles around. My house stands in the midst of these 
A HS Hin! kp ca gh lage 9 
MANA 
