138 PROCEEDINGS OF THE NATIONAL MUSEUM vol.85 



paper will serve its purpose by calling attention to the existence of 

 such phenomena and that future research workers will recognize that 

 this area is worth a careful investigation. Plate 1 shows a map of 

 the region and the localities where types were taken. 



LARVAL TRAILS IN THE PETRIFIED WOOD 



On many of the fossil trees in the Petrified Forest National Monu- 

 ment there are peculiar ridges and shallow channels, some of which 

 completely encircle the massive trunks. To the average observer 

 these are just "funny" marks on the trees, but when examined care- 

 fully they seem to indicate that they were made by some form of 

 animal life. Tlie more they are studied the more I am convinced that 

 they were made by some insect (larvae) that had attacked the forest. 

 These ridges, channels, and tunnels apparently represent the bur- 

 rows and cuttings of the larvae of wood borers or bark beetles. 



Two different groups are recognized; one is represented by chan- 

 nels that were apparently just under the bark; the other by tunnels 

 or burrows cut through the heart-wood, some around the outside of 

 the tree but sometimes penetrating 40 or 50 cm from the outside, 

 while others bored through and through the wood in all directions. 



Several "species" of each grouj) seem to be present. In order to 

 distinguish these different forms, the following method of classifi- 

 cation and description has been adopted : 



GROUP 1 



This group consists of channels, not tunnels, that for the most 

 part occur apparently just under the bark. The cuttings evidently 

 are coming partly from the heart-wood. In some cases the cuttings 

 were silicified and now form raised bands around the tree trunks. 

 In some others the cuttings dropped out, leaving shallow channels. 

 In this group there are three species, as follows : 



PALEOBUPRESTIS MAXIMA, new genus and species 

 Plate 2 



Type 5;?ecmen.— U.S.N.M. no. 95870. 



Refen^ed specimen. — Petrified Forest Nat. Mon. Mus. no. 101. 



Type locality. — Petrified Forest National Monument, Holbrook, 

 Ariz. 



Formation. — Triassic (Chinle) . 



Description. — These channels seem to occur just under the bark. 

 They measure about 10 mm across and may be followed completely 

 around the tree; in some instances channels measure from 1 to 2 

 meters in length. The cuttings made by the lar^'a as it worked 

 along show exceptionally well. Wliere the cuttings were silicified in 



