21 
Francisco, but these are quarantined and inspected in California by 
horticultural inspectors, so that not much is to be feared from that 
quarter. More is to be feared from the Gulf of Mexico coast lines and 
railway communication. 
DANOER FROM WEST INDIAN PORTS. 
Our Southern States stand in much danger from West Indian ports, 
especially from Cuba, which is in close communication with them by 
steamships and sailing vessels. Sixty-five or more species of scales are 
known from Jamaica. Seventeen of these occur out of doors in the 
Southern States, eight more being known in hot-houses there. Only 
four species of scales are so far recorded from Cuba. Compared with 
Jamaica, Cuba ought to have 75 or 100 species. Many species have 
doubtless been brought from Cuba to our Southern States, and others 
are apt to follow if not guarded against. Frequent boats run from 
Tampa, Fla., to Key West and Habana, and return by same route. It 
is only 90 miles across from Key West to Habana. Frequent boats run 
from Cuba to other ports in the Southern States. 
CONDITIONS WHICH RETARD THE SPREAD OF INJURIOUS INSECTS IN 
MEXICO. 
It is a peculiar fact that in Mexico the natural conditions are such as 
to retard the spread of injurious insects of certain groups; while, on 
the other hand, artificial conditions that spread insects in our own 
country are happily such at present as to give little aid to their disper- 
sion in Mexico. I refer, first, to the topography and resultant isolation 
of climatic regions in Mexico; and second, to the fact that shipments 
of fruit, etc., by rail are not made from on e to the other of these regions 
These observations apply best to orange insects. The following is a 
good case in point : 
It has already been mentioned that the orange worm (larva of Try- 
peta ludens) infests the oranges to a very great extent in the State of 
Morelos. It was known in that region many years ago, and does not 
seem to occur yet in any other orange region. Inquiries were made 
at Guadalajara, where I was told that wormy oranges were unknown, 
and I have never known of wormy oranges from the Cordova or Orizaba 
region, many of which I have examined. Likewise they were not heard 
of in Tamaulipas or Sonora. The explanation of this is that the Morelos 
orange region is effectually isolated from others by climatic barriers in 
the shape of ranges upon ranges of mountains where the orange can not 
thrive, even were these ranges not in the original wild state, and also 
that the oranges shipped from the infested localities in the State of 
Morelos go no farther than Mexico City, where they are all sold and 
consumed. 
The same holds good in several instances of scale insects of the 
orange. Orthezia insignis var. was found only in Guadalajara and 
