MUD WALLS. 181 



construct a common nest. The nest is extremely variable in 

 form, because it depends much, on the number of twigs which it 

 includes. Interiorly, it is divided into a considerable number 

 of chambers, each containing one or several individuals. 



As the caterpillars are hatched late in summer, they have to 

 undergo the frosts of winter before they can attain their psrfect 

 state. Accordingly, before the winter-time comes on, they 

 strengthen both the external walls and internal partitions of 

 their nest, and then wait until the spring brings forth the 

 leafage of the new year. 



The nest is a beautiful structure, and I strongly recommend 

 the reader to look for one in a hedgerow, take it home, and 

 cut it up carefully. I would, however, advise him, if, like 

 myself, he be subjected to a very sensitive skin, to be cautious 

 in his handling of the nest. The hairs with which the pretty 

 black, red, and white caterpillars are studded are irritant in 

 the extreme. 



I have several times suffered from them, and would much 

 rather be severely stung by nettles than undergo the fierce irri- 

 tation, mixed with dull heavy pain, which always accompanies 

 the presence of these hairs. With me, as I suppose would be 

 the case with persons of similar organization, these hairs cause 

 large, hard tubercles to rise, j ust as if potatoes had been placed 

 under the skin. The hairs of the Processionary Caterpillar have 

 a similar effect, and in France the authorities have several times 

 been obliged to close the public gardens for months, so severe 

 was the pain which the caterpillars inflicted on persons who 

 passed through the spots infested by them. 



Mud Walls. 



There is a mode of wall-building which is much in vogue in 

 some parts of England, and has much to commend itself. This 

 is the Mud or Concrete Wall. 



At first sight, the very name of a mud house gives an idea of 

 poverty and misery, and is apt to be connected with hovels 

 and pigsties. Mud walls, however, if properly built, are far 

 warmer and drier than those of brick, and are even preferred to 

 those of stone, when the latter can be easily and cheaply 

 obtained. In Devonshire, for example, where even the cattle- 

 sheds, or "linhays" (pronounced linny), and the pigsties are 



