3 54 LEPIDOPTERA 



these resemblances we have a case of hj'pertely similar to that 

 of the resemblance to Insects' minings exhibited by certain marks 

 on the tegmina of Pterochroza (mentioned in \o\. Y. p. 322). 



In South America there is a somewhat peculiar genus of 

 Nymphalides — Agerunia — that delights in settling on the trunks 

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

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

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

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

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

 frighten away enemies. Bigg-"\Vether found, however, that in 

 South Brazil there is a lazy little bird to which this 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 quite clear. Sir 

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

 the extreme base 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 sonrce 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 frequently remarkable, character. In Apatura and 

 its allies the body is without armature, but the head is perpen- 

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

 caterpillar of our Purple 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 head 

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

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

 Ajxitura, 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 has six perfectly formed legs, though the front pair is smaller. 

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

 tarsi unfointed, without claws. This family consists of about 1000 



^ P. Zool. Soe. London, 1892, p. 191. 



