41 8 LEPIDOPTERA 



when the creature becomes numerous it thus reduces the food 

 supply, so that its own numbers are afterwards in consequence 

 diminished. 



One of the most remarkable genera of British Noctuidae is 

 Acronycta? the larvae of which exhibit so much diversity that it 

 has been suggested that the genus should be dismembered and its 

 fragments treated as allied to several different divisions of moths. 

 There are many points of interest in connection with the natural 

 history of these Acronycta. A. psi and A. ridens are practically 

 indistinguishable as moths, though the larvae are easily separated : 

 the former species is said to be destroyed to an amazing extent 

 by parasites, yet it remains a common Insect. The genus 

 Apatela is very closely allied to Acronycta, and Harris says that 

 " Apatela signifies deceptive, and this name was probably given to 

 the genus because the caterpillars appear in the dress of Arctians 

 and Liparians, but produce true owlet-moths or Noctuas." ' The 

 species of another British genus, Bryopliila, possess the excep- 

 tional habit of feeding on lichens. Some of the American group 

 Erebides are amongst the largest Insects, measuring seven or 

 eight inches across the expanded wings. 



The Deltoid moths are frequently treated as a distinct family, 

 Deltoidae, perhaps chiefly because of their resemblance to Pyra- 

 lidae. At present, however, they are considered to be separated 

 from Noctuidae by no valid characters. 



Fam. 38 Epicopeiidae. The genus Epicopeia consists of 

 only a few moths, but they are amongst the most extraordinary 

 known : at first sight they would be declared without hesitation 

 to be large swallow-tail butterflies, and Hampson states that they 

 " mimic " the Papilios of the Polyxenus group. Very little is 

 known about these extremely rare Insects, but the larva is stated, 

 on the authority of Mr. Dudgeon, to surpass the moths themselves 

 in extravagance ; to be covered with long processes of snow-white 

 efflorescence, like wax, exuded from the skin, and to " mimic " a 

 colony of the larva of a Homopterous Insect. Some ten 

 species of this genus are known from Java, India, China, and 

 Japan. In this family there is said to be a rudimentary frenu- 

 lum, but it is doubtful whether the hairs that have given rise to 

 this definition really justify it. 



1 See Chapman, The Genus Acronycta and its Allies, London, 1893. 

 2 Insects Injurious, etc., Ed. 1862, Boston, p. 437. 



