ILLUSTRATIONS 



PLATES. 



Page. 



Plate I. Work of the pine-destroying beetle of the Black Hills 8 



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 wood-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 w T hen 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 



5 



