354 LEPIDOPTERA chap. 



these resemblances we have a case of hypertely similar to that 

 of the resemblance to Insects' minings exhibited by certain marks 

 on the tegmina of Ptcrockroza (mentioned in Vol. V. p. 322). 



In South America there is a somewhat peculiar genus of 

 Nymphalides — Agcronia — that delights in settling on the trunks 

 of trees rather than on flowers or leaves. It was long since noticed 

 that the species of Aycronia make a clicking noise ; in some cases 

 when on the wing, in other cases by moving the wings when the 

 Insect is settled. The oljject of the noise is quite uncertain ; it 

 has been suggested that it is done in rivalry or courtship, or to 

 frighten away enemies. Bigg-Wether found, however, that in 

 South Brazil there is a lazy little Ijird to which tliis sound serves 

 as a signal, inducing it to descend from its perch and eat the clicker. 

 The mode in which the noise is produced is not cpiite clear. Sir 

 George Hampson has pointed out ^ that the fore wing bears at 

 the extreme l)ase a small appendage bearing two hooks, and that 

 two other processes on the thorax play on these when the wing 

 moves. His suggestion that these hooks are the source of the 

 sound seems highly probable. 



There is a great variety in the larvae of Nymphalides. In 

 the Vanessa group the body is armed with spines, each one of 

 which bears shorter thorns, the head being unadorned. The 

 Fritillaries (Argynnis, Melitaea) also have caterpillars of this kind. 

 In many other forms the head itself is armed with horns or spines 

 of diverse, and freipiently remarkable, character. In Apatura and 

 its allies the l»ody is without armature, but the head is perpen- 

 dicular, the vertex bifid and more or less prolonged. The 

 caterpillar of our I'urple Emperor, Apatura iris, is quite unlike 

 any other British caterpillar ; in colour it is like a Sphingid 

 larva — green with oblique lateral stripes of yellow and red — but 

 in form it is slug-like, pointed behind, and it has on the liead 

 two rather long tentacle-like horns. In the South American genus 

 Frepona, the larva of which in general form resembles that of 

 Apatura, there are no anal claspers, but the extremity of the body 

 is prolonged, forming a sort of tail. 



Fam. 2. Erycinidae (Lemoniidae of some authors). — The 



female lias sic perfeetly foruied legs, tlioaglt the front piair is smaller. 



The male has the coxae of the front legs forming a spine, and the 



larsi unjointcd, icithont clavs. This family consists of about 1000 



1 7'. Zool. Sue. London, 1892, p. 191. 



