16 March 1973
Vol 179, Issue 4078

About The Cover

Larval aggregation of the sawfly Neodiprion rugifrons on its host, Pinus banksiana. The mature larvae are displaying one of the alarm reactions that reduce attacks by parasites and predators: a raising of the anterior and posterior segments from the needle surface, at the same time exuding orally a drop of gummy fluid. Mature larvae are about 20 millimeters long. See page 1090. [G. Knerer, University of Toronto]