8 
BULLETIN 184, U. S. DEPARTMENT OF AGRICULTURE. 
they produce a grinding noise that can be heard several feet away, 
and when the branch is disturbed this noise is more pronounced. 
The pupae in turn make a somewhat similar noise when disturbed, 
and for this reason one must raise the bark covering in order to 
know just when transformation takes place. 
Before the pupal stage of this species could be had the writer was 
transferred to Indiana, and the material was taken there in order 
to obtain the pupae. The branches were examined frequently during 
the months of June and July, but no pupae were observed until 
August, and the first adult beetle emerged September 15. The dura- 
tion of the pupal stage is approximately four weeks, with an average 
mean temperature of 72.5° F. 
There is only one generation of this beetle each year, approximately 
12 months being required for the life cycle from egg to adult. 
LONGEVITY. 
The beetles that emerged in the laboratory were kept in confine- 
ment without fresh food and lived from 4 to 12 days, while those 
that were captured, confined in the insectary, and furnished proper 
food lived from 10 to 21 days, the males dying from 1 to 5 days in 
advance of the females. 
NATURAL ENEMIES. 
There are several species of parasites that attack the eggs and 
larvae of Oncideres putator, one species in particular attacking both 
egg and larva. The following were reared February 3, 1915, at 
Brownsville, Tex.: Chryseida inopinota Br., Eurytoma sp. (Chttn. 
No. 1921), C aenophanes sp. (Chttn. No. 1922), a pteromalid (Chttn. 
No. 1923), and Meteorus sp. (Chttn. No. 1924). It is thought that 
the larvae have one or more predaceous enemies, but none has been 
observed to this writing. It is believed that the southern downy 
woodpecker (Dryobates pubescens) and probably also the Texas 
woodpecker {Dryobates scalaris bairdi) attack the larvae. While 
neither of these birds has been found with larvae, they have been 
observed at work on branches that contained numerous larvae of this 
insect and have left empty chambers behind. 
Table I shows something of the mortality early in the season. 
Table I. — Mortality of the huisache girdler, based on examinations made Janu- 
ary 8, 1913. 
Number of branch. 
Diameter 
of branch 
(milli- 
meters). 
Number of 
eggs. 
Number of 
live larvae. 
Number of 
dead 
larva*. 
I 
26 
30 
35 
28 
32 
37 
11 

19 


7 

58 
153 
197 
173 
52 

II 
3 
III. 
2 
IV 
14 
V 
17 
VI... 

