2 BULLETIN 184, U. S. DEPARTMENT OF AGRICULTURE. 



were known to injure the pecan. In any case, the huisache was of 

 sufficient vahie to warrant a thorough investigation of the girdler, 

 as it holds front rank as a shade tree in the newly developed 

 country in the lower Eio Grande Valley. When the girdlers were 

 first found and observed at work they were exceedingly abun- 

 dant, and there was no difficulty in collecting a large number in 

 a very short time. A shipment was immediately made to Wash- 

 ington, where Dr. Chittenden identified the insect as Oncideres 

 putator, and later Mr. E. A. Schwarz confirmed this determination. 

 Since the girdler was first observed, its work has become more con- 

 spicuous each successive season. In 1913, over the infested area as a 

 whole, the beetles appeared in lesser numbers, but in places they 

 were more abundant and the damage was greater than at any time 

 during the four years previous. This would indicate that climatic 

 conditions were not altogether responsible for the decrease, as some 

 of the infested areas were near and in close proximity to one another. 

 It is believed that natural enemies were responsible in part, if not 

 wholly, for the lack of uniformity in distribution in 1913. 



The beetles (PI. I) possess powerful mandibles and saw with ease 

 branches If inches in diameter, completely severing them from the 

 main body of the tree. The eggs, as with other twig girdlers, are 

 deposited in the severed portion of the branch, and never below 

 where it is girdled. The writer has observed as many as 63 girdled 

 branches from one tree, some of which measured 40 millimeters in 

 diameter, the average ranging from 22 to 35 millimeters. (See PI. 

 II.) No other girdler has been observed to prune branches of this di- 

 ameter, and all near relatives with which we are acquainted prune 

 or girdle much smaller branches. Oncideres putator, unlike some 

 girdlers, does not work so much in pairs, but is often found in colo- 

 nies as well. The girdling is usually begun a few inches from the 

 base of the branch selected for oviposition or just above where it 

 joins the body of the tree or larger branch, though cases have been 

 observed where the attack was directed to the middle of the branch. 

 At times after the sawing has been begun by one female beetle others 

 will begin depositing eggs before the girdling is very far advanced, 

 apparently with little fear that the branch will not be completely 

 girdled in due time. Young trees are often girdled only a few inches 

 above ground, but where large trees are adjacent the beetles seem 

 to prefer attacking the branches instead. (Pis. Ill, IV.) 



In view of the fact that in the lower Rio Grande Valley and other 

 parts of the Southwest where much development in farm lands is in 

 progress, and where the huisache is oftentimes the only shade tree 

 found upon a farmer's premises, it is thought advisable to present 

 here for publication the life history, food plants, and habits of this 

 girdler, with suggestions for control. 



