2 BULLETIN 95, U. S. DEPARTMENT OF AGRICULTURE. 



of Entomology. 1 This bulletin gives further facts regarding the 

 character and extent of damage to the seed of coniferous forests 

 of the Pacific slope. It also furnishes preliminary information 

 on the more important groups of insects causing this damage, and 

 their habits, that it may be available to seed collectors during the 

 present spring and summer. 



CHARACTER AND CAUSE OF DAMAGE. 



Damage to the seed of conifers is caused by various species of 

 insects which feed upon the buds, flowers, immature cones and seed, 

 and mature seed. Great damage is accomplished while the cones 

 are immature and before the seed ripens. Cones which are infested, 

 or "wormy," are often found when the areas for seed collection are 

 being located. Wormy cones and seeds are caused by the adults 

 and grubs of small beetles, the "worms" or caterpillars of moths, the 

 maggots of gnats, and the larvae of tiny wasps known as seed chal- 

 cidids. In his work the seed collector usually encounters these im- 

 mature stages of insects which depend upon the cone scales and seeds 

 as their principal source of food supply. With the exception of the 

 cone beetles the adult insect is seldom found in the immature cone. 

 The insects may be found in almost any part of the cone or seed, the 

 feeding habits varying much with the different species. In many 

 cases the presence of these insects in the cone is evident and may be 

 recognized by the peculiar type or class of injury. Where this is the 

 case the damage may be approximately estimated during the summer. 



With the more important seed-infesting insects the damage will be 

 recognized in one or more of the following classes: 



BLIGHTED CONES.2 



The cones are sometimes killed when small and immature. As a 

 result they wither and dry, and none of the seeds fill. Cones so 

 affected are often described as blighted. Most of the injury of this 

 character occurs in the cones of pine and is caused by the cone beetles. 

 The attack is usually on the second-year cones, although the small 

 first-year cones are sometimes killed. Some of the cone worms, also, 

 bore into the cones in such a manner as to kill them and cause the 

 same blighted condition. Sugar-pine cones attacked by the beetle 

 nearly always fall to the ground during July and August. The cones 

 of other species usually adhere to the tree for a winter or two. Damage 

 of this type is easily recognized and can be estimated after the middle 

 of July. 



1 Ilopkins, A. D., Catalogue of exhibits of insect enemies of forests and forest products at the Louisiana 

 Purchase Exposition, St. Louis, Mo., 1904. U. S. Dept. Agr., Div. Ent., Bui. 48, p. 13-14, 33, 1904. 



Hopkins, A. D., Insect enemies of forest reproduction. U. S. Dept. Agr. Yearbook, 1905, p. 250-251, 

 1906. (Yearbook Separate 381.) 



Rohwer, S. A., VI, Chalcidids injurious to forest-tree seeds. U. S. Dept. Agr., Bureau of Entomology, 

 Tech. Ser. 20, Pt. VI, p. 157-163, Feb. 10, 1913. 



* PI. I, figs, cl , d; PI. II, figs, a, b. 



