23 



INJURY TO DEAD WOOD AND BARK BY POWDER-POST BEETLES. 

 ORDER COLEOPTERA, FAMILY PTINIDiE. 



PART OW CASE 17. 



60. The Pine Wood Perforator {Ptinid?). 



Small white grubs burrow through the dead wood of western yellow-pine logs, 

 causing rapid decay. Grants Pass, Oreg. 

 Exhibit: Work. 



61. The Giant Arbor Vitae Ptinid (Ptinid) . 



Small white grubs boring in the dead heartwood of living giant arborvitae, con- 

 tributing to the rapid decay of the heartwood. Port Angeles, Wash. 

 Exhibit: Work. 



62. The Giant Arbor Vitae Dryophilus (Dryophilus sp.). 



A small whitish grub and brownish beetle, breeding in the outer bark of the giant 

 arborvitse. Its work is very common. Detroit, Oreg., and Port Angeles, Wash. 

 "Kepresents a European family and genus heretofore unrecorded from North 

 America. ' ' ( Schwarz. ) 



Exhibit: Work. 



INJURY TO TWIGS BY BARK MAGGOT. ORDER DIPTERA, FAMILY 



CECIDOMYinXffi. 



'PAET OIP CASE 17. 



63. The Pine Twig Mag-got (Cecidomyiid). 



Minute reddish maggot, living in the bark of terminal twigs of the western yellow 

 pine, causing the leaves to turn yellow and die. Moscow Mountains, Idaho. 

 Common. 



Exhibit: Work. 



INJURY BY GALL INSECTS. ORDER HEMIPTERA, FAMILY 



APHIDLEXffi. 



CASE 18. 



64. The Sitka Spruce Gall-Louse (Chermes sibiricus f). 



A minute insect forming cone-like galls on the terminal twigs of the Sitka spruce 

 at Newport, Oreg. Very common and injurious to young trees. 

 Exhibit: Work. 



65. The Englemann Spruce Gall-Louse {Chermes sibiricus f, var. ). 



Same habit as 64, but probably a variety or different species. Common on Engle- 

 mann spruce at Sand Point, Idaho. 

 Exhibit: Work. 



INJURY BY CICADA. ORDER HEMIPTERA, FAMILY CICADIDiE. 



CASE 18. 



66. Small Western Cicada {Cicada sp.). 

 Injuring twigs of Douglas spruce, St. Helen, Oreg. 

 Exhibit: Adult and work. 



INJURY BY TWIG-MINER. ORDER LEPIDOPTERA, FAMILY 



TORTRICIDiE. 



CASE 18. 



67. The Pine Twig-Miner {Tortricid). 



A caterpillar of a moth with similar habits to that of the pine moth of Nantucket, 

 excavating burrows through the pith of the terminal twigs and shoots of young west- 

 ern yellow pine. Moscow Mountains, Idaho, where it was common and quite 

 injurious. 



Exhibit: Work. 



