ion ■ 



PARASITIC ENEMIES. FAMILY ICHNEUMONIDiE. 



257. The Lunated Long-Sting'. 



Thalessa lunator Fab. 



There are several quite similar species of these insects, whicli, by means of the long, 

 thread-hke appendage to the body, deposit their eggs within the galleries of the 

 horntail larva", upon which their own larvte are parasitic. 



Exhibits: Adults. 



INJURING INNER BARK. 



THE BARK-BEETLES. FAMILY SCOLYTIDiE. 



258. The Pine-Destroying Beetle of the Black Hills.- 



Dendroctonus pondcfusm Hopk. 



Attacks liealthy pine and spruce in the Black Hills of South Dakota and Rocky 

 INIountain region. The adult beetles excavate characteristic galleries in the inner 

 bark of dead, dying, and healthy trees. Their eggs are deposited along the sides of 

 these galleries, and the larvie developing from them mine the inner l)ark. It is esti- 

 mated that it has been the primary cause of the destruction of 1,000,000,000 feet of 

 western yellow jdne [J'inus poriderosa) in the Black Hills. 



Exhibit: Adults, work. Sections of trunks of western yellow pine attacked by 

 beetles showing pitch tubes on surface and marks of galleries in inner bark. 



C^^SE 45. 



259. The Destructive Pine Bark-Beetle. 



Dendroctonus frontalis Zimm. 



Attacks healthy pine and spruce in the Southern States. It is capable of enormous 

 destruction and, though usually held in check l)y natural causes, has at various times 

 past so increased as to seriously menace the entire stand of pine and spruce in por- 

 tions of tlie Southeastern States, notably in West Virginia in 1891-92. 



Exhibit: Adults, work. Markings on surface of wood of beetle-killed tree; appear- 

 ance of outer bark of beetle-killed trees; outer bark of tree scaled off by woodpeckers 

 in search of beetles and their larvse. 



260. The Oregon Tomicus. 



Tornicu!^ orcyutii Eich. 



A secondary enemy of pine, attacking and hastening the death of trees primarily 

 attacked by the ]iine-destroying beetle. 



Exhibit: Work. Section of top of western yellow pine, showing galleries of adult 

 beetles in inner bark. 



261. The Companion Bark-Beetle. 



Tomicus imdsns Eich. 



A common species infesting pine in the Southern States. When abundant it attacks 

 and kills healthy trees, but it is'especially common as a secondary enemy in com- 

 pany with the destructive bark-beetle Dendroctonus frontalis Zimm. 



Exhibit: Adults, work. 



CASK l<>. 

 262. The Lawson Cypress Bark-Beetle. 



Pldteosinns cupresscC Hopk. 



Attacks transplanted Lawson and Monterey cypress in California. It also attacks 

 redwood. 



Exhibit; Adults, work. 



