INSECTS BORING IN THE ROCKY MOUNTAIN SPRUCE. 859 



these circumstances I have little doubt but that it bores iuto this tree. 

 There is a great disparity in size and color between the sexes, and the 

 male is much the smaller and is blue-black, with most of the elytra deep 

 brick-red, the ends of the elytra being blue-black, as well as an oblong 

 oval spot at the base of the united elytra -, the terminal two-thirds of 

 the abdomen is reddish ; it is 16™'" long ; the female is 21""" long, and 

 entirely blue-black. It was identified by Dr. Horn. 



6. Scolytus unispinosus Lee. 



Mr. J. B. Smith gives the following account of this borer in Entomo- 

 logica Americana, ii, 1886, p. 125. 



A few days since (July 12, 1886) Mr. L. E. Ricksecker, of Sylvania, Occidental P. O., 

 Cal., sent me a section of Douglass spruce {Abies doHglassii) infested by a Scolytid, 

 about whicli he writes as follows : "The wood is a small section from the upper limb 

 of a Douglass spruce, which was cut down on April 9, 1886. Many species of Coleop- 

 tera attacked the treo on the same evening in a perfect swarm. Next day and there- 

 after but few of these were seen. Other species, however, made their appearance, 

 and among these were numbers of Scolytus unispinosus Lee. For a week I could see 

 them moving hurriedly up and down the limbs of the prostrate tree. Then they be- 

 came less, and by May 6 only a few stragglers could be found. 



Noticiug 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, jiresumably the male, being at the opening, and the other at 

 the far end. At that date, Maj' 6 to 10, the burrows were about an inch long ; now 

 (July 4), the main burrow is two to three inches long, with about twenty-six 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 im- 

 pression of their galleries on the wood. When full-grown they turn towards the 

 surface and there await their transformations." 



To this interesting account of Mr. Ricksecker a few notes based on the specimen 

 (now in the National Museum) and on the literature may be not uninteresting. 



The specimen shows two complete main galleries with the larval galleries — about 

 30mm — a length of If inches — at inegular intervals on each side. These extend at first 

 at right angles with the main gallery, but become sinuous almost immediately, and the 

 larvae change their direction, working upwards above and downwards below the mid- 

 dle of the main burrow. Those larvoe nearest to the center work longer at right angles, 

 but eventually turn either upward or downward, and sometimes change the course of 

 the gallery. One gallery shows a larva that first worked at right angles for adistance, 

 and then started downward until it came very close to another gallery. Rather than 

 enter this it changed its course ; went obliquely upward for a distance, and then again 

 turned downwards at right angles. Two larval galleries from the same main gal- 

 lery rarely cross eacli other, but sometimes two main galleries are close together, and 

 then the larval galleries cross and recross in the wil, est confusion. The main galleries 

 are sunken about as deeply into the wood as in the bark ; but the larval galleries 

 are deeper in the bark. At the point of entrance there is an enlargement of the 

 gallery, of a size sufficient to permit the beetle to turn. 



There are also, in the specimen, five main galleries, with either no larval galleries 

 at all or just started. One of these galleries is interesting, for here the beetle came 

 in, formed a small cell, and started downward for half an inch, then changed its 

 mind, and turning, started upward for about an inch. In the main galleries no eggs 

 seem to be laid within 4™"i of the entrance. Before the parent beetle has finished 



