24 POPULAR SCIENCE MONTHLY. 



bending it under its body. Beginning again the same movements, 

 it is not long in producing a second globule of liquid, filled with air 

 like the first, which it places side by side with and close to the pre- 

 ceding one, and continues the same operation as long as there re- 

 mains any sap in its body." Kirby and Spence, in their Entomology, 

 describe " the white froth often observed on rose bushes and other 

 shrubs and plants, called by the vulgar ' frog spittle,' but which 

 if examined will be found to envelop the larva of a small hemip- 

 terous larva {Aphropliora spumaria), from whose anus it exudes." 

 In Westwood's Insects we find the following statement: " One of 

 the best-known insects in the family is the Aphropliora spumaria, 

 a species of small size which frequents garden plants, the larva and 

 pupa investing themselves with a frothy excrementitious secretion 

 which has given rise to various fancies. A species of Aphropliora 

 is also found in great quantities upon trees in Madagascar, the 

 larva of which has the power of emitting a considerable quantity 

 of clear water, especially in the middle of the day, when the heat 

 is greatest." Here the statement is definitely made that the froth 

 is excrementitious, and the Madagascar insect is shown to be differ- 

 ent from Aphropliora in that it exudes a clear water. In Dr. Har- 

 ris's Treatise on some of the Insects Injurious to Vegetation, of 

 Massachusetts, we find a most definite statement as to the origin 

 and nature of this froth. He says: "Here may be arranged the 

 singular insects, called frog hoppers (Cercopididw), which pass their 

 whole lives on plants, on the stems of which their eggs are laid in 

 the autumn. The following summer they are hatched, and the 

 young immediately perforate the bark with their beaks and begin 

 to imbibe the sap. They take in such quantities of this that it 

 oozes out of their bodies continually in the form of little bubbles, 

 which soon completely cover up the insects." In Dr. Packard's 

 admirable Guide to the Study of Insects the statement is made that 

 " Helochara and Aphropliora, while in the larva state, suck the sap 

 of grasses and emit a great quantity of froth, or in some cases a 

 clear liquid, which in the former case envelops the body and thus 

 conceals it from sight. It is then vulgarly called ' toad's spittle.' " 



In other accounts it is stated that the larvas live covered by 

 masses of froth which the insects produce by expelling from their 

 beak the juices drawn out of the tree. 



The above extracts are sufficient to indicate the common belief 

 among entomologists that the insect in some way emits this froth 

 from the body. A most cursory examination of the creature, how- 

 ever, shows that its only secretion is a clear fluid. 



The so-called frog spittle or cuckoo spit (Fig. 1) appears as little 

 flecks of froth on grass, buttercups, and many other plants during 



