244 Forty-second Report on the State Museum. [102] 



tinguished Swedish naturalist, lias given an elaborate account of the 

 observations made by him on the method of the spittle production. 

 Wishing to obtain definite knowledge in relation to it, he removed 

 one of the insects from its frothy coverings, wiped it dry with a 

 camel's-hair pencil, and placed it on a freshly cut stalk of honeysuckle 

 in a glass of water. The following is his account of what he saw: 



It begins by fixing itself on a certain part of the stalk, in which it 

 inserts the end of its trunk, and remains there for a long time in the 

 same attitude, occupied in sucking and filling itself with the sap, 

 Having then withdrawn its trunk, it remains there, or else places itself 

 on a leaf, where after different reiterated movements of its abdomen, 

 which it raises and lowers and turns on all sides, one may see 

 coming out of the hinder part of its body a little ball of liquid, 

 which it causes to slip along, bending it under its body. Beginning 

 the same movements again, it is not long in producing a second 

 globule of the liquid, filled with air like the first, which it places side 

 by side with, and close to the preceding one, and continues the same 

 operation so long as there is any sap left in its body. It is very soon 

 covered with a number of small globules, which, coming out of its 

 body one after the other, tend toward the front part, aided in this 

 by the movement of its abdomen. It is all these globules collected 

 together which form a white and extremely fine froth, the viscosity of 

 which keeps the air shut up in the globules and prevents its froth 

 from easily evaporating. If the sap which the larva has drawn from 

 the plant is exhausted before it feels itself sufficiently covered with 

 froth, it begins to suck afresh, until it has drawn a new and sufficient 

 quantity of liquid, which it takes care to add to its first stock. 

 (Memoires pour sermr a VHistoire des Insectes, Tome 3.) 



In another place DeGeer makes this positive statement : " The 

 globules have absolutely no other issue than from the anus." 



Purpose of the Secretion. 

 As to the purpose served by this liquid covering, it has been con- 

 jectured that it has the effect of protecting the delicate-skinned 

 insect from the burning heat of the sun, for it can not live long if 

 withdrawn from it, for the insect soon shrinks and speedily dies. It 

 is thought also that the covering protects it from carnivorous insects 

 and other enemies, that but for this concealment would prey upon it. 

 It does not, however, give it entire immunity, for some of the larvae 

 collected by me at West Albany had been visited with a parasitic attack, 

 and several Chrysopa larvae were found in such association with the 

 spittle masses that they were undoubtedly preying upon the insects 

 concealed within. 



Description of the Insect. 

 Uhler has briefly characterized it as of a claret-brown color above, 

 marked with two pale bands on the vertex, two on the prothorax, and 

 a wavy, broader band on the wing-covers. The membrane is often 



