4 BULLETIN 95, U. S. DEPARTMENT OF AGEICULTUEE. 



spread to dry. They are among the most common insects noted in 

 the work of seed collecting. 



IMPORTANT GROUPS OF SEED-INFESTING INSECTS. 



There are four important groups of insects which cause practically 

 all of the serious damage under the four classes described. 



CONE BEETLES. 



Cone beetles are small, dark, cylindrical beetles which attack the 

 cones of pines. The cones are killed by the attack of the adult, 

 which bores a small tunnel into the axis to deposit its eggs. (PI. II, 

 fig. hi.) The larvae (PL I, fig. d) feed on the seeds and scales of the 

 withering cone and develop to the beetle stage within the dead cone, 

 where the beetles usually remain over winter. The attacks of several 

 species of these beetles are very common in western yellow pine and 

 sugar pine. The damage to crops of sugar pine is considerable, as 

 these beetles have been noted in some seasons to kill from 25 to 75 

 per cent of the cones over large areas. 



CONE WORMS. 



Cone worms are most frequently met with in the cones in the 

 caterpillar stage. They represent several species of moths which 

 infest the cones of pines, firs, hemlocks, and spruces, and even the 

 seed of incense cedar has been found to be attacked by the tiny larvae. 

 The moths are small and in most species dull colored and inconspicu- 

 ous. The small white larvae of one species are very common in the 

 cones of western yellow pine and Jeffrey pine. They feed upon the 

 seeds and scales without killing the cone and overwinter as larvae 

 and pupae in galleries in the pith of the cone axis. (PI. I, fig. b.) 

 Another species is a very common enemy of Douglas fir seed on the 

 Pacific slope. The larvae mine a gallery through the scales, leaving 

 an opening at the surface through which resin and larval castings 

 exude. The pupae overwinter near the axis in resinous cocoons among 

 the scales. Nearly all species feed without killing the cone, but a 

 large caterpillar feeding on western yellow pine sometimes kills the 

 immature cone, the damage resembling that of the cone beetle. 



SEED CHALCIDIDS. 



The adults of seed chalcidids are tiny wasps (PL III, fig. d) . The 

 larvae (PL III, figs, b, d) five within the seeds, apparently developing 

 as the seeds grow, so that the infested seeds reach normal size and 



Explanation of Plate I.— a, Photograph near Bray, Cal., showing cones of western yellow pine on 

 ground, but poor reproduction; b, mature western yellow pine cone, showing pith occupied by the cone 

 worm and seeds destroyed by it; cl, blighted western yellow pine cone caused by the cone beetle; c2, 

 normal cone; d, young living western yellow pine cone, greatly enlarged, to show character of damage 

 by the cone beetle and its larvae. (Original.) 



