BRITISH MOTHS 



THEIR TRANSFORMATIONS. 



FAJIILY X. 

 GEOMETRID^. 



This family is of scarcely less extent than the Noctuidse, from which, as well as from the Linnaean Bombyces, 

 its species are distinguished by the general weakness of structure and slenderness of body, but more particu- 

 larly by the remarkable peculiarities and geometric mode of progression of the caterpillars ; whence has been 

 derived the family name, derived from the Greek, and meaning " measurers of the ground." The head is of 

 moderate size ; the maxillae short and weak, being nearly membranous ; the labial palpi small and cylindrical • 

 the antennce variable, being strongly bipectinated in the males of some species, but simple in otliers ; the wings 

 are of large size and of various outline, being often extended horizontally, although in a few species they are 

 carried vertically. We here find no traces of the curious characteristic markings of the Noctuidse : the thorax is 

 never crested ; the legs are slender ; the anterior tibife being armed internally with a spur, and the posterior 

 with two pairs of those appendages. 



The caterpillars are called loopers, or geometricians, and have generally three pairs of pectoral, and only one 

 (the hindmost) pair of ventral prolegs, with a pair of anal feet ; and hence, in walking, they first fix themselves 

 firmly by means of their anal and ventral feet ; they tlien extend the body to its greatest length, fixing themselves 

 by their fore feet, and then drawing the hind part of tlie body as close after them as possible, so as to form an 

 arch, like a pair of compasses, fixing their hind feet, and proceeding again as before. Their muscular power is 

 very great, and hence their positions during repose are very striking. Fixing themselves by their anal feet 

 alone, they extend their bodies in a straight line, directed upwards, and holding themselves at an angle in this 

 position for a great length of time. This, together v^'ith their obscure colours and the warts which their bodies 

 exhibit, renders it often quite difficult to distinguish them from the twigs of the trees on which they 

 feed. Mr. Stephens describes the larvae of some genera as possessing twelve, and others fourteen feet ; and in 

 a species figured by De Geer (Mem. torn. i. pi. 25, fig. 1 — 7), the larva has three pairs of ventral feet, the first 

 and second of which are very minute. These caterpillars vary in their outward appearance, as will be seen by 

 comparing our different plates. They feed on the leaves of various trees and plants, and have the instinct, when 

 alarmed, of dropping from the leaves and suspending themselves by a thread, which enables them to remount 

 when the danger is past. The chrysalides are of a conical form, with the head rounded. They are either naked 

 or suspended by the tail, or inclosed in a very slender cocoon, which is rarely subterranean, and ofttimes placed 

 amongst dry leaves, &c. 



In the perfect state, these insects offer very little variation in their habits, fl3nng sluggishly in the twilight 

 or when disturbed during the day, and quickly settling again amongst the foliage of woods and hedges. la 



VOL. II. B 



