8 BULLETIN 243, IT.. S. DEPARTMENT OF AGRICULTURE. - 



duced the food supply of the squirrels, so that by the middle of July, 

 when the serious cutting by the squirrels began, there was very little 

 of the crop left for them. 



Many large sugar pines standing on prominent ridges where they 

 could easily seed several acres of the slopes below have failed to 

 accomplish this result. One area which the author has studied closely 

 is situated just above Colestin. Oreg.. where a heavy fire in 1910 

 killed most of the timber on several sections, although a number of 

 large seed-producing sugar-pine trees distributed over the area 

 were but little injured. (PL I, figs. 1, 2.) However, in 1911 scarcely 

 any sugar-pine seedlings could be found near these trees. Evidence 

 that this area has been heavily infested by the cone beetle since the 

 fire is plentiful, and in 1911 it destroyed 75 per cent of the crop, the 

 squirrels completing the damage as shown in Table II under area 1. 



Either the cone beetle or squirrels, but more probably a combina- 

 tion of the two. is responsible for the absence of satisfactory repro- 

 duction in situations where it is much needed. 



THE WESTERN YELLOW-PINE CONE BEETLE. 



(Conoplithorus ponderosae Hopk.) 



The general life cycle of the cone-beetle broods in yellow pine does 

 not differ in any important respect from that in sugar pine. The 

 first attack on second-year cones has been noted to occur from two 

 to three weeks earlier. The period of maximum emergence occurred 

 from May 1 to 15 on two small lots observed. Close observations on 

 the period of attack and development in this host were made near 

 Ashland at elevations from 1.800 to 2.200 feet. This is from 1.500 

 to 2.000 feet lower than the elevations at which similar observations 

 were made on the beetles in the sugar pine. The comparative differ- 

 ence in seasonal history as shown by these observations will be found 

 in Table I. 



The first attack of adults in 1911 was noted on May 5. but the 

 adults were only just starting to bore into the cone and no egg 

 gallery had been commenced. From May 10 to June 1 continued 

 fresh attack was noted, and the latest fresh attack occurred on June 

 10. By June 3 the earliest attacked cones contained a few pupa? 

 and were beginning to turn brown and wither, so that they could 

 easily be distinguished from the normal green, unattached cones. 

 By June 15 pupae and a few new adults were found in the cones first 

 attacked and very little fresh attack was noted. The gradual trans- 

 formation of the brood progressed through the latter part of June 

 and the first part of July, and by July 15 new adults were infesting 

 practically all cones. 



