AmeriqAna 



TOL. II. BROOKLYN, OCTOB. & NOVEMB. 1886. NO. 7&8. 



Notes on Scolytus unispinosus, Lee. 



By John B. Smith. 



A few days since (July 12, '86.) Mr, L, E..Ricksecker of Sylvania, 

 Occidental P.O. Calif, sent me a section of Douglass spruce [Abies doug- 

 lasii) infested by a Scolytid, about which he writes as follows: "The 

 wood is a small section from the upper limb of a Douglass spruce, which 

 was cut down on April 9th '86. Many species of Coleoptera attacked 

 the tree on the same evening in a perfect swarm. Next day and there- 

 after but few of these were seen. Other species however made their ap- 

 pearance, and among these were numbers of Scolytus unispinosus Lee. 

 For a week I could see them moving hurridly up and down the limbs of 

 the prostrate tree. Then they became less, and by May 6th only a few 

 stragglers could be found. 



Noticing that something was boring in these limbs and throwing out 

 little piles of dust, I cut out patches of bark, and found in every case two 

 Scolytus occupying a straight gallery; one, presumablv the male, being 

 at the opening, and the other at the far end. At that date, May 6th to 

 10th, the burrows were about an inch long — now (July 4th) the main 

 burrow is two to three inches long, with about 26 side galleries on each 

 side, diverging therefrom. The parent beetles are gone, but at the end 

 of each side gallery is a larva, working farther and farther away from the 

 main gallery. They work only in the layer of bark nearest the wood 

 leaving a slight impression of their galleries on the wood. When full 

 grown they turn towards the surface and there await their transforma- 

 tions." 



