234 



INTRODUCTION TO ZOOLOGY 



is said to be wetted at first by the water and to breathe 

 through its skin, but later the spiracles become functional ; 



when this has happened it is found 

 that the body, under water, looks 

 silvery owing to the air surround- 

 ing it, and the case now becomes 

 impermeable to water. The larva 

 hibernates through the winter and 

 pupates in May, creeping out of 

 the water on some plant stem, to 

 which it fixes its case, then spin- 

 ning a little silken cocoon, within 

 which it changes to the pupa (Fig. 

 162, c). 



The moths are inconspicuous, 

 whitish-grey forms, with a little 

 darker marking on the wings. 

 When folded, the hinder margins 

 of the wings appear pleated, and 

 the scales of the wing overlap 

 each hind margin as a little fringe 

 (Fig. 162, d). 



The Brown China Mark {Hydro- 

 eampa nympheata), in its larval 

 stage, makes a much neater pro- 

 tective case by biting a little oval- 

 shaped piece out of a large leaf, 

 and then cutting out another piece 

 of the same size, and binding the 

 two together with silk to form a 

 little hollow, lens-shaped covering over the body. 



Tussock "^^^ Tussock Moths are rather small, dull- 



Moths coloured forms, the males of which have very 

 (Liparidae or conspicuously pectinate (comb-like) antennae (see 

 Lymantriidae). -p:^^ 163, Jf). The females are often wingless, 

 and the larvae usually have noticeable tufts or tussocks of hair 

 on them. These hairs tend to come out when the caterpillar 

 is handled, and to cause irritation and sometimes a rash on the 

 skin of any one handling them. 



The Vapourer Moth (Orgyia antiqiM) is one of these 

 "Tussocks." The caterpillar (Fig. 163, L) is of a pretty 



FiQ. 162. — Stages in the Life of 

 the Small China Mark Moth. 



e, Eggs under a leaf of frogbit ; a, 

 caterpillar removed from its 

 case ; &, caterpillar in its duck- 

 weed case ; c, pupa ; d, imago. 



