ILLUSTRATIONS, 



PLATES. 



Page. 



PLATE I. Work of the pine-destroying beetle of the Black Hills & 



II. Work of the coarse-writing bark beetle 8 



III. Work of the pine-destroying beetle of the Black Hills. Fig. 1. 



Primary galleries and larval mines in inner bark. Fig. 2. Marks 



of primary galleries on surface of scoring chip 12 



IV. Work of the pine-destroying beetle of the Black Hills. Fig. 1. 



A, Primary galleries, larval mines, pupa cases, and exit holes; 



B, Primary galleries grooved in surface of wood in chip cut from 

 railroad tie. Fig. 2. Evidence of cutting living trees. A, Scor- 

 ing chip from railroad tie, showing surface of wood not marked 



by insects; B, Showing inner surface of bark from same chip 12 



V. Work of the Oregon Tomicus. Fig. 1. A, Galleries engraved in 

 surface of wood cut from old dead tree; B, Bark with inner 

 portion destroyed by galleries and larval mines. Fig. 2. Gal- 

 leries in inner bark and surface of wood of railroad ties and edg- 

 ing strips 16 



VI. Work of the rock-pine w r ood-engraver (Pityogenes cariniceps Lee.). 



Galleries in inner bark and surface of wood 16 



VII. Scenes in the pine forests of the Black Hills Forest Reserve work 

 of Dendroctonus ponderosa Hopk. Fig. 1. Small freshly attacked 

 pine tree, showing pitch tubes. Fig. 2. Marks of primary gal- 

 leries on the surface of wood when bark is removed. Fig. 

 3. Freshly attacked tree, showing pitch tubes; adjoining tree 

 not attacked. Fig. 4. Dead tree, outer bark removed by 

 woodpeckers 20 



TEXT FIGURES. 



FIG. 1. Work of the pine-destroying beetle of the Black Hills 9 



2. Work of the Oregon Tomicus 10 



3. Work of the Oregon Tomicus 11 



4. Work of the Oregon Tomicus 12 



5. Work of the rock-pine wood-engraver 13 



