107 



forth remarks from the presiding officer, the Secretary 

 and others. 



In the evening an instructive lecture was delivered in 

 the church by the President of the Society, Dr. Andrew 

 Nichols of Danvers,* "On the Advantages of the Study 

 of Nature," which closed this interesting day. 



After mentioning the meetings of the Institute held in 

 this place in September, 1859, and June, 1860, and the 

 cordial receptions extended on these occasions, he called 

 upon Mr. E. S. Morse to give some account of his obser- 

 vations during the forenoon's ramble. 



Mr. E. S. MORSE of Salem, after a few remarks on the 

 findings of the day, gave a description of the insect 

 which is the cause of the froth found on grass. This 

 froth goes by the name of frog spit, and is supposed by 

 many to be made by frogs, while others are aware that 

 the substance in question is made by insects, but sup- 

 pose the insects to be young grasshoppers. They are 

 quite different from the grasshopper, belonging to an 

 entirely different order. The creature causing this froth 

 matures into a little wedge-shaped bug called leaf hopper, 

 an hemipterous insect, the Ptyelus lineatus of Fitch. The 

 eggs are deposited in the autumn, and are hatched in the 

 following summer. In their larval or immature condi- 

 tion only are they surrounded by this frothy substance. 

 It has been stated that these insects excrete their frothy 

 covering, whereas they excrete a clear liquid, and blow 

 it up afterward. This they accomplish by reaching out 

 of the fluid their posterior segments and clutching, as it 

 were, a drop of air, which they drag within the fluid 

 holding it for a while against the under surface of the 



* See page 89 of this volume; also Proceed. Essex Inst., Vol. i, page 49 and Vol. 

 ii, page 26. 



