HABITS AND LIFE HISTORY. 49 
MEANS OF DISTRIBUTION. 
From an economic standpoint, the important considerations in the 
means of spread of this insect arc those which affect its wide distribu- 
tion from one part of the country to another. The transportation by 
nursery stock or scions or budding and grafting material, as indi- 
cated in the foregoing account of this insect, is unquestionably 
usual and principal means oi carrying the insect to a distance. The 
importance of this means of distributing various insects has only been 
fully realized in this country in the last few years, but the present 
instance and some other notable ones of like nature have emphasized 
the great danger incurred not only in the indiscriminate introduction 
of plants from foreign sources, but also in the carriage of plants from 
one part of the country to another without competent inspection. 
The San Jose scale is also frequently carried about on fruit, as the 
young very commonly crawls out upon the fruit, particularly with the 
pear, and is thus shipped to remote points. It may be frequently 
thrown out on parings and the young larva may uain access in this 
way to trees. This method of transportation was strikingly illustrated 
at the meeting of the Association of Economic Entomologists held in 
Brooklyn, in 1894, when Prof. ,1. 13. Smith exhibited a number of Cali- 
fornia pears purchased from the nearest fruit stand, all of which were 
badly infested with the scale, showing many full-grown females and in 
some cases young larva 1 crawling about. Such fruit is sold on all trains 
and in practically all large towns in the United States. Prof. J. W. 
Tourney states Bulletin 14. Arizona Experiment Station.]). 36) that he 
has purchased California pears and apples in the fruit stalls of Phoenix 
and Tucson infested with both female and male scales, and Prof g 
Smith reports a like experience in the markets of Philadelphia, Newark, 
New York, and Brooklyn. The danger of infestation from parings and 
rejected fruit will therefore be easily understood. 
The spread of the insect from orchard to orchard and from tree to tree 
must also be brought about through the agency of means other than I 
under the control of the insect itself. The female is wingless, and after 
once becoming tixed. can not move. The young lice, as before stated, are 
active, crawl rapidly, and may reach other trees, but this is rare unless 
the limbs interlace, since we have shown by breeding-cage experiments 
that the larva' normally crawl but a lew inches. Such spread, however, 
is comparatively insignificant except in the case of nursery stock, which 
is grown close together. It is possible that strong winds may carry the 
young bodily from one tree to another, or. they may be floated on water 
to distant points, particularly in irrigated districts, but the principal 
method of the spread of these young lice is by means of other insects, 
and by birds. The active young lice soon crawl upon any small winged 
8090— Xo. 3 1 
