41 



PARASITIC ENEMIES. FAMILY ICHNETJMONITXffi. 



PAET OF CASE 43. 



257. The Lunated Long-Sting- (Thalessa lunator Fab.). 



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

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

 horn tail larvae upon which their own larvse are parasitic. 



Exhibit: Adults. 



INJURING INNER BARK. 



THE BARK-BEETLES. FAMILY SCOLYTIDiE. 



CASE 44. 



258. The Pine-Destroying Beetle of the Black Hills (Dendroctonus ponderosx 

 Hopk.). 



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

 Mountain 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 larva? developing from them mine the inner bark. It 

 is estimated that it has been the primary cause of the destruction of 1,000,000,000 

 feet of bull pine (Pinus ponderosa) 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. (Large 

 case. ) 



CASE 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 by natural causes, has at various times 

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

 of the 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 larvae. (Large case. ) 



260. The Oregon Tomicus' (Tomicus oregoni Eich.) . 



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

 attacked by the pine-destroying beetle. 



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

 beetles in inner bark. (Large case. ) 



261. The Companion Bark-Beetle (Tomicus avulsus Eich.). 



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

 attacks and kills healthy trees, but is especially common as a secondary enemy in 

 company with the destructive bark-beetle Dendroctonus frontalis Zimm. 



Exhibit: Adults, work. 



CASE 46. 



262. The Lawson Cypress Bark-Beetle (Phlceosinus cupressse Hopk.). 



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

 redwood. 



Exhibit: Adults, work. 



263. The Hickory Bark-Beetle (Scohjtus quadrispinosus Say). 



A common bark -beetle in hickory, frequently causing the death of trees. The 

 adults also do some damage by gnawing the base of small twigs, causing their death. 

 Exhibit: Adults, work. 



