276 



(see for example De Geer, more recently Porter and Fabre, also 

 for curious American forms, Ball.) The name of "Cuckoo Spit," 

 applied to these forms in Europe, dates from classic times, when 

 il: was believed that the insects were born from the saliva of 

 cuckoos; the French "Crachat de Grenouille" indicates cred- 

 ence in another supposed origin. The adults are termed "Frog- 

 hoppers" in England. The nymphs and adults of Philagra parva 

 swarm in Australia on Casiiariiia trees, the former enveloping 

 themselves in froth after the manner of Ccrcopis. The nymph of 

 the Madagascan Ptyclus goudoti Bennett, possesses the power of 

 discharging clear water in such considerable quantities as to 

 resemble light rain, this activity being naturally greater at noon- 

 tide. Goudot estimated that some seventy individuals could 

 emit a quart in an hour and a half. 



It has been stated (see, for example, Amyot & Serville) that 

 the nymphs are thus enveloped to guard them from carnivorous 

 insects; on the contrary, DeGeer notes, what has been often ob- 

 served since, viz : that these nymphs are frequently ravished 

 from their spume by small Fossorial Hymenoptera, while Birds 

 are also said to prey upon them. The froth in reality serves to 

 j*rotect their soft bodies from the heat of the sun, as when taken 

 from this cover and not allowed moisture with which to re-en- 

 velope themselves, they soon shrivel up and perish. 



Certain Australian forms, however, construct calcareous cases 

 of helicoidal or serpulideous form and attach them to twigs ; 

 usually of Eucalyptus. These cases were discussed twenty years 

 ago by Ratte since when nothing original has been published on 

 them. 



The case is fixed to a twig from two to seven feet above the 

 ground, generally a little or immediately above the insertion of 

 a leaf; and its opening is turned upwards. The shape varies ac- 

 cording to genus and species. Some figured by Ratte are ac- 

 tually helicoidal, from this they uncoil till forms are found which 

 are quite or almost straight, though tapering, the widening 

 from the base of course corresponding to the growth of the 

 nymphs. PfllychacfopJiycs Kirkaldy has larger, coarser tubes, 

 somewhat stalactitic in ornamentation, while those of Pccfiua- 

 riflphycs Kirkaldy are smaller and more delicate. The position 

 of the larva within is reversed, the head being placed down- 

 V ards, (Ratte says that the helicoidal form is an exception,) so 

 that the anus is found at the mouth of the tube. Under cover of 

 the case, at the basal end of which is a slit, the nymph sucks the 

 sap of the tree ; occasionally it moves backwards and emits a 



