Elm Borers and Elm Bark Louse : Elm Borer (Sapreda tridentata Oliv.). 1. Larva or grub within its burrow just under the bark; 1a, Larva or grum extended; 2. Pupa within its cell just under the bark; 3. Burrows of the grub as exposed after removal of the bark; 4. Adult beetle.. Elm Snout Beetles (Mardalis): 5. Adult of Magdalis armicollis Say; 6. Adult of magdalis barbita Say; 6a. Side view of same; 7. Larva of Magdalis barbita, side view; 8. Pupa of Magdalis barbita within its oval cell just beneath the bark; 8a Empty pupal case of Magdalis barbita; 9. Burrows of Magdalis barbita as exposed after removal of the bark; 9a. Holes in the bark through which the beetles escape; 9b. Showing how bark is loosened by the burrows of this insect.; Elm Bark Louse (Gossyparia ulmi Geoff): 10. Group of partly grown bark lice as they appear in the early spring; 11. Group of male cocoons; 12. Group of male cocoons; 13. Group of females; 14. Female; 15. Recently hatched young; 16. Mature female; 16a, Mature females on a twig; 17. Pesudimago or wingless male; 18. Winged male.... Note also the long, white, anal filaments