8 THE COLORADO EXPERIMENT STATION 
3 in the orchard, at which time several winged specimens were seen in 
process of fertilizing the matured females. Examination of infested 
trees at Grand Junction, February 9, 1907, showed the male larvae 
beneath the scales already with their black eyes apparent. No pupae 
were yet formed. Material taken indoors upon twigs has yielded males 
as early as February 22. The males seemingly emerge throughout 
the greater part of the summer. 
Early in June many newly hat:hed insects of both sexes were 
beginning to crawl actively over the bark. By June 9 many had set¬ 
tled down, thickly covering the bark with the early summer brood. Some 
were upon the small pears also and .others were seen upon the upper 
and lower leaf surfaces. Many at this date had well developed scale 
coverings already secreted over them. Oval eggs, pale yellow and with 
blunt ends, were found,showing the females to be oviparous rather 
than viviparous as in the case of the San Jose scale. The exact time 
required for hatching is evidently short for through the summer are 
usually to be seen from one to a dozen minute yellowish-orange 
colored and newly hatched young.beneath each of these scale coverings 
along with small clusters of eggs. In cases, no eggs but only dusters 
of the very minute young, are to be found beneath the female scales and 
it has been suggested by Professor Gillette that they are occasionally 
born living. 
In Western Colorado it is probable that at least three and perhaps 
four generations are developed during the season, including those 
living through the winter in an immature stage. These generations, 
however, greatly overlap one another making a continuous succession 
of individuals appearing throughout the season. 
MEANS OF DISTRIBUTION. 
The most common method of distribution of scale insects over 
long distances is well known to result from the shipment of infested 
nursery stock. Since almost all of the new orchard plantings within 
the state are of nursery stock from states free from this pest, and as 
little nursery stock is shipped away at present, this phase of the 
question does not appear to be of any particular consequence. 
The local transmission of the insect is largely dependent upon 
outside forces as the only time during which the female has power 
of locomotion is for the short period from its hatching beneath the 
scale covering to the time it settles down to feed at a fixed point 
upon the plant. This interval of activity is, however, of short dura¬ 
tion and no great distance can be traversed in the time by so small 
an insect. Except for dispersal over single trees the insect must 
depend upon outside agencies in spreading. Such agencies are the 
wind, other crawling and flying insects upon the trees, as ants and 
lady beetles, birds and chickens or live stock at large in orchards. 
Irrigation ditches evidently transport the minute active individuals 
which have been blown or washed from infested trees. It is also 
likely that the common operations of the orchard, such as cultivation. 
