GEOMETRY. 199 



elongated, with a slight elevation on each ' segment of the 

 abdomen. 



The moth appears in February or March, and flies in the 

 day-time. 



GEOMETRY. 



This is an extremely natural group of Moths, and most of the 

 species belonging to it are easily distinguishable from those of 

 any other group. As a rule they are of moderate size, rarely 

 exceeding two or three inches in expanse, and have slender 

 bodies, and broad, brightly-coloured wings, the hind-wings being 

 nearly as large as the fore-wings, and more or less similarly 

 coloured. In the males the antennae are often strongly 

 pectinated ; but the bodies of the insects are seldom clothed 

 with rough hair, except in certain genera with stout instead of 

 slender bodies. The females of some species, especially those 

 which appear in winter or in early spring, are apterous. 



But the most characteristic feature of the Geometra is the 

 structure of the larvae, which have only ten legs, the first three 

 pairs of pro-legs being absent, or at least imperfectly developed. 

 These larvae fix themselves by their claspers and pro-legs to a 

 leaf or branch, and then stretch their bodies stiffly out, in 

 which position they often remain for a long time, when they 

 look deceptively like bits of dry stick. When walking, they 

 extend their bodies as far as they can reach, take hold with 

 their front legs, then draw up the hind ones, arching the back 

 as they do so, and then extend their bodies again, thus 

 proceeding by a succession of loops, whence they are called 

 Geometrce, or "Land Measurers"; or, in English, " Loopers." 



Guenee, in his " Uranides et Phalenites," published in 1857 

 (vide vol. iv. pp. xxx. 166), divided the Geometrse into twenty- 

 six families, of which seventeen are represented in Britain. 

 Dr. Packard, in his " Monograph of the Geometrid Moths or 



