420 LEPIDOPTERA chap. 



much concealed by overlapping scales), giving entrance to a 

 chamber in the body ; this chamber extends to the middle line, 

 being separated from its fellow by only a thin partition. At 

 its anterior and lateral part there is a second vesicle -like 

 chamber, formed by a delicate membrane that extends as far 

 forwards as the base of the abdomen. There can be little doubt 

 that this is part of some kind of organ of sense, though it is 

 much larger than is usual with Insect sense-organs. 



Fam. 40. Epiplemidae. — Under this name Hampson has 

 assembled certain Geometroid moths, some of them placed previ- 

 ously in Chalcosiidae, some in Geometridae. They form a varied 

 group, apparently closely allied to Uraniidae, and having a similar 

 peculiar sense-organ ; but are distinguished by the presence of a 

 frenulum. The larva seems to be like that of Uraniidae. 



Fam. 41. Pyralidae. — This division is to be considered rather 

 as a group of families than as a family ; it includes a very large 

 number of small or moderate-sized moths of fragile structure, 

 frequently having long legs ; antennae simple, only in a few 

 cases pectinate ; distinguished from Noctuidae and all the other 

 extensive divisions of moths by the peculiar course of the costal 

 nervure of the hind wing, which either keeps, in the middle of 

 its course, near to the sub-costal or actually unites with it, 

 subsequently again separating. Members of the Pyralidae are 

 found in all lands; in Britain we have about 150 species. The 

 larvae -are usually nearly bare, with only short, scattered setae, 

 and little coloration ; they have most varied habits, are fond of 

 concealment, and are very lively and abrupt in movement, 

 wriggling backwards as well as forwards, when disturbed; a 

 cocoon is formed for the metamorphosis. 



The family as a whole consists of Insects of unattractive 

 appearance, although it contains some very elegant and interesting 

 moths and numerous forms of structural interest. In the genus 

 Thiridopteryx little transparent spaces on the wings occur as a 

 character peculiar to the males ; tlie spaces are correlative with 

 a greater or less derangement of the wing-nervures. In some 

 other forms there is a remarkable retinaculum, consisting of large 

 scales, and this, too, is connected with a distortion of the wing- 

 nervures. The Pyralidae — Pyralites of Eagonot,^ Pyralidina of 



^ Ragonot, Ann. Soc. ent. France, 1890 and 1891 ; and Meyrick, Tr. ent, Soc. 

 London, 1890, p. 429. 



