— r?6 — 



To this interesting account of 'Sir. Ricksecker a few notes based on 

 the specimen (now in the National IMuseuni) and on the Hterature, may 

 be not uninteresting. 



The specimen shows two complete main galle- 

 ries with the larval galleries — about 30 in a length 

 of one and three-quarter inches — at irregular in- 

 tervals 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 downward.s 

 below the middle of the main burrow. Those 

 larvae nearest to the centre 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 a distance and then started downward un- 

 til it came very close to another gallery — rather than 

 enter this it changed its course, went obliquely up- 

 ward for a distance and then again turned downwards 

 at rightangles. Two larval galleries from the same 

 main gallery rarely cross each other, but sometimes two main galleries 

 are close together and then the larval galleries cross and re-cross in the 

 wildest 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 mm. of the entrance. Before the parent beetle has finished its burrow 

 the eggs laid nearest the entrance have hatched and the larval galleries 

 will be from 3 — 4 mm. in length at the entrance before the last eggs are 

 deposited. 



In general appearance the galleries of unispinosus resemble most 

 nearly those of the European Sc. iniricaius. But the most interesting 

 point in Mr. Ricksecker's communication is the food tree. No other 

 species o{ Scolytus whose food habits are recorded lives on Conifers. All 

 attack deciduous trees. So striking a departure from the general habits 

 of the genus is rather remarkable and furnishes another instance of the 

 dangers of "reasoning from analogy". Mr. E. A. Schwarz has kindly 



