450 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 14 



in control methods are being developed constantly at the Bureau's 

 western experiment stations under the direction of Dr. A. D. Hopkins. 

 These improvements mean cheaper protection and the investigative 

 work which yields them should not be sacrificed. There is a real need 

 for the study of forest insect problem.s by the state experiment stations. 

 With the rapidly growing demand by the forest industry for advice on 

 forest insect control, the necessity for the enlargement of the Bureau's 

 personnel of forest entomologists and the need for the attention of the 

 state experiment stations to the many still unsettled phases of the forest 

 insect problem are already at hand. 



BIOLOGICAL NOTES ON DESMOCERUS, A GENUS OF 



ROUNDHEAD BORERS, THE SPECIES OF WHICH 



INFEST VARIOUS ELDERS 



Bj' H. E. Burke, Specialist in Forest Entomology, 

 Bureau of Entomology, U. S. Dept. of Agric. 



The Genus Desmocerus consists of four western and one eastern spe- 

 cies. All bore in the pith and wood of living shrubs or trees of various 

 species of elder (Sam_bucus). As some of the elders are used as omam.en- 

 tal shrubs or shade trees these insects which infest them are of interest as 

 shade tree pests. Usually the stems mined by the borers do not die but 

 sometimes they do and in any case the emergence holes made by the 

 beetle cause unsightly scars in the bark and afford an easy entrance to 

 wood destroying bacteria, fungi and ants. 



In general the life cycle of Desmocerus is two years. Eggs are laid 

 in crevices of the bark or around wounds and the larva does most of its 

 boring in the pith of the stems. Lateral mines are made through the 

 wood to the surface of the bark for throwing out borings and for the emer- 

 gence of the adult. Pupation and the transform.ation to the adult take 

 place during the second spring in a cell in the pith. The adults em^erge 

 about the tim.e the elder is in bloom and may be found on the flowers or 

 foliage. The best m.ethod of collecting them, however, is to cut into the 

 stem.s just before the flowers open and take them from the pupal cells. 



All of the species have been collected and studied to som_e extent by the 

 writer. Special attention has been given to crihripennis and calif ornicMS 

 because they occur in the Pacific region and because calif ornicus causes 

 damage to the blue berried elder which is a comjmon door^-ard shade tree 

 in central California. Mr. R. D. Hartm.an of the Los Gatos Forest 

 Insect Laboratorv' made a number of notes on the life histors^ of calif orni- 

 cus and Miss E. T. Annstrong of the Washington office collected most 

 of the auripennis studied. 



