680 



AN INTRODUCTION TO ENTOMOLOGY 



ments there is on the middle of the back of each an eversible gland 

 supposed to be a scent-organ similar to the osmateria in the larvae 

 of Papilio, and it is stated that a fine spray of liquid is sometimes 

 thrown from them. 



Fig. 850. — Hemerocam- 

 pa leucostigma. 



Excepting a few rare forms 

 our native species pertain to 

 the genera Hemerocampa, Noto- 

 lophus, and Olene. In the first 

 two of these genera the males 

 are winged and the females are 

 nearly wingless. In Olene both 

 sexes are winged. Our best 

 known of the native members 

 of this family are the follow- 



Fig. 849 

 tigma. 



2d A 

 -Wings of Hemerocampa leiicos- 



The white-marked tussock- 

 moth, Hemerocampa leucostig- 

 ma. — This is our most com- 

 mon representative of the family. It frequently occurs in such great 

 niimbers that it seriously injures the foliage of shade-trees and or- 

 chards. The male (Fig. 850) is of an ashy gray color; the fore wings 

 are crossed by undulated bands of darker shade and bear a conspicu- 



Fig. 851. — Hemerocampa leucostigma, larva. 



ous white spot near the anal angle. The female is white and resembles 

 a hairy grub more than a moth. She emerges from her cocoon and 

 after pairing lays her eggs upon it, covering them with a frothy mass. 

 The larva (Fig. 851) is one of the most beautiful of our caterpillars. 



