vi HETEROCERA AGARISTIDAE GEOMETRIDAE 411 



The nude of the Indian Aegocera tripartite^ has been noticed 

 to produce a clicking sound when flying, and Sir G. Hainpson has 

 shown l that there is a peculiar structure on the anterior wing ; 

 he considers that this is rubbed against some spines on the front 

 feet, and that the sound is produced by the friction. Though 

 this structure is wanting in the acknowledged congeners of 

 A. tripartite, yet it occurs in a very similar form in the genus 

 Hecatesia, already noticed under Castniidae. 



Fam. 36. Geometridae (Carpets, Pugs, etc.} This very 

 extensive family consists of fragile moths, only a small number 

 being moderately stout forms; they have a large wing - area ; 

 the antennae are frequently highly developed in the males, 

 but on this point there is much diversity. Either the frenulum 

 or the proboscis is absent in a few cases. The caterpillars are 

 elongate and slender, with only one pair of abdominal feet 

 placed on the ninth segment in addition to the anal pair, or 

 claspers. They progress by moving these two pairs of feet up to 

 the thoracic legs, so that the body is thrown into a large loop, and 

 they are hence called Loopers or Geometers. The family is uni- 

 versally distributed, and occurs even in remote islands and high 

 latitudes ; in Britain we have about 270 species. The family was 

 formerly considered to be closely connected with Noctuidae, but at 

 present the opinion that it has more intimate relations with the 

 families we have previously considered is prevalent. Packard 

 considers it near to Lithosiidae, while Meyrick merely places the 

 six families, of which he treats it as composed, in his series Noto- 

 dontina. Hampsou adopts Meyrick's six families as sub-families, 

 but gives them different names, being in this respect more con- 

 servative than Meyrick, whose recent revision of the European 

 forms resulted in drastic changes in nomenclature. 2 This 

 classification is based almost exclusively on wing-nervuration. 

 The number of larval legs and the consequent mode of walking- 

 is one of the most constant characters of the group ; the few 

 exceptions that have been detected are therefore of interest. 

 Anisopteryx aescularia has a pair of undeveloped feet on the eighth 

 segment, and, according to Meyrick, its allies " sometimes show 

 rudiments of the other two pairs." The larva of Himera 



1 P. Zool. Soc. London, 1892, p. 188. 



2 Tr. ent. Soc. London, 1892, pp. 53-140 ; for criticism on the nomenclature, 

 see Rebel, Ent. Zeit. Stettin, liii. 1892, p. 247. 



