298 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 

 40. Tremex columba (Linn.). 



From the following letter, which we have received from Mr. James 

 Angus, of West Farms, N. Y., it seems probable that Tremex columba 

 injures the hickory by boring into the trunks. So good and exper- 

 ienced an observer as Mr. Angus would not think of referring the 

 writer to the attacks of this borer if there were not some foundation for 

 his suspicions. 



The hickory trees are all dying around here. I should say that one-half of the 

 trees have died within two or three years. In woods that are not crowded and of 

 mixed woods it is quite common to find as many as from three to six dead trees 

 within a stone's throw. Great numbers of Rhyssa atrata and lunator are now to be 

 seen on the trunks of partially decayed trees. Earlier in the season the Tremex were 

 also abundant. Can it be the latter insects that are doing all this mischief ? 



Mr. Tyler Townsend confirms Mr. Angus' statement in a note re- 

 ceived while this report was passing through the press. 



In regard to Tremex columba I have found large numbers of the dead adults in 

 February in a standing, dead trunk of hickory in Michigan. They were found as 

 they had died in their burrows, being unable to penetrate the hard bark or else having 

 perished from parasites, for numerous remains of Rhyssa were present. In every case 

 the heads of the unfortunate Tremex pointed towards the bark, which they had 

 been unable to pierce. 



41. Osmoderma eremicola (Knoch). 



This beetle has been observed by Mr. W. H. Harrington to feed 

 *' upon the sapi)y, partly decayed wood, enlarging the wound and caus- 

 ing further decay, and thus injuriously affecting the tree. He found 

 the insect in the pupa state, inclosed in oval cocoons made from parti- 

 cles of the wood, in a small hollow where decay had commenced from 

 the breaking off of a limb. The cocoon is made in autumn, the beetle 

 appearing the following July. Its larva is said to closely resemble the 

 common white grub, or young of the May beetle. 



AFFECTING THE BARK. 



42. The hickory-bark louse. 



Lecanium caryw (Fitch). 



Order Hemiptera ; family CocciD^. 



Fixed to the bark of the small limbs, a large, very convex oval scale of a black 

 color fading to chestnut brown, in May dusted over with a white powder. Length 

 often 0.40 by 0.25 inch in width. (Fitch.) 



43. The hickory blight. 



Eriosoma caryw (Fitch). 



Order Hemiptera ; family Aphid^. 



Forming a flocculent down coating the under side of the limbs, especially of bushes 

 and young trees in shaded situations, multitudes of wooly plant lice. 



Winged individuals. — Black, with the head, scutel, and abdomen covered with a 

 white cotton-like substance, the fore wings with an oval salt-white spot near the tip 

 of their outer margin, the veins being obsolete. Length to the tip of the winga 0.12 

 inch. On walnut bushes in Illinois. (Fitch.) 



