8 



BULLETIN 184, U. S. DEPAETMENT OF AGRICULTURE. 



they produce a gi'inding 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 

 Qgg and larva. The following were reared February 3, 1915, at 

 Brownsville, Tex.: Chryseida inopinota Br., Eurytoma sp. (Chttn. 

 No. 1921), Caenophanes 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 {Dryohates pubescens) and probably also the Texas 

 woodpecker {Dryobates scalaris hairdi) 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, tased 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 



Ill 



2 



IV 



14 



V 



17 



VI 











