Doering: Lepyronia quadrangularis. 527 



They probably move from lack of food or because of disturbances, 

 and in the field, if they find a favorable place, they may stay in one 

 place throughout their period of growth. 



The size of the spittle mass varies for each instar, being in pro- 

 portion to the size of the nymphs. The first-instar nymphs, at least 

 the recently hatched ones, are covered by a clear drop of fluid with 

 very little foam, and for this reason are easily discovered in the 

 field. In fact, they were originally discovered by means of these 

 clear drops of fluid. When walking through the weeds the writer's 

 attention was attracted by these shiny drops of fluid on the vegeta- 

 tion, and upon closer examination it was found that they came 

 from the spittle nymphs, which were usually found on the under 

 sides of the leaves, and for this reason are not easily seen. The 

 spittle masses of the other instars are usually foamy and puffy in 

 the field. 



When the insect is ready to transform into an adult an interest- 

 ing change in the spittle mass takes place. The superficial part of 

 the foam dries and stiffens somewhat, so that it forms a roof to a 

 closed chamber. Within this chamber the molt occurs, and the adult 

 can be seen distinctly in this mass. It usually takes a day for the 

 adult to harden sufficiently to emerge. If they are removed from 

 the mass too soon they do not gain their full color, but have a yel- 

 lowish-tan appearance. When the adult is ready to emerge the 

 slightest disturbance causes it to give a strong leap, thus freeing it- 

 self from the spittle ball and leaving a round opening in the latter. 

 Empty chambers are found quite frequently in the field. 



In captivity all the instars made comparatively little spittle. In 

 a good many cases they lived chiefly in the fluid without producing 

 many bubbles. When the spittle was produced it usually was just 

 sufficient to cover them. The fourth- and fifth-instar nymphs were 

 able to make the most spittle, but even these did not reach the 

 proportion of those in the field. 



The process of froth-making in the Cercopidae has been a topic of 

 discussion for some time. The earliest conception of the spittle 

 masses was that they were voided by tree frogs. Fabre (1900), in 

 the discussion of froth-making by Aphrophora spumarius, which in 

 his picturesque way he calls the "cicadelle," says that the peasants 

 of France give another name to this substance. They call it "cuckoo 

 spit," because the little balls occur at the time of year when this 

 bird returns from its migrations. The early entomologists assigned 

 the spittle to its correct cause, but they thought that the foam 



