THE HUISACHE GIRDLER. \) 
On January 13, 1913, four primings of huisache were stripped of 
bark, and the following table made : 
Table II. — Infestation of the huisache girdler by parasites, based on examinations 
made January 13, 1913. 
Number of branch. 
Diameter 
of branch 
(milli- 
meters). 
Number of 
eggs. 
Number of 
living 
larvae. 
Number of 
larvae par- 
asitized. 
I 
36 
30 
25 
38 



59 
363 
104 
79 
135 
11 
II 
5 
Ill . 
6 
IV 

These tables give the degree of infestation to a single branch and 
the mortality of the larvae at a very early date. The parasites of the 
larvae are more numerous a little later in the season, although the 
egg parasite appears even as early as December 1. This parasite is 
more effective against the larvae before they approach a size more 
than two-fifths of an inch in length; although it attacks the larvae 
throughout the season it does not appear in as large number then 
as it does early in the season. 
METHOD OF CONTROL. 
Since this insect spends at least 10 months in the severed branch 
during the egg, larval, and pupal stages, its control is only a matter 
of collecting the pruned branches and destroying them by burning. 
This would not be a laborious task, as the girdled branches are so 
large that it is not difficult to locate them, and as the species does not 
appear to migrate very rapidly to new territory, this method would 
nearly eradicate the species in isolated localities, at least, in one or 
two seasons' time, taking it for granted that a few branches might go 
unnoticed. (See PI. Ill, fig. 2.) The work of burning the branches 
could best be done from the first week of January to the first of Au- 
gust, as the writer has not observed the laying of any eggs as late as 
January 1. As the huisache wood burns readily, it should be com- 
paratively easy to collect and destroy pruned branches from a large 
number of trees in a comparatively short time. In addition to this 
measure, the beetles might be collected by hand where one has only a 
small number of trees to guard against this girdler, and in this way 
the trees could be protected before any damage had been done. 
WASHINGTON : GOVERNMENT PRINTING OFFICE : 1916 
