142 NATURAL HISTORY OF ARTHROPODS. 



yellowish-green. They occur everywhere in gardens, and a common species has been 

 observed by us to lay its eggs, from late in August until the last of October, on the 

 leaves of the lilac, pear, and horse-chestnut. The eggs are oblong-oval, not numerous, 

 and are covered by a flat, round web, like the ' cocoon ' of a spider, but only about 



a line in diameter. The development of the embryo requires but 

 jp ^. a few days, and the process of development appears to be substan- 

 tially like that of other Pseudoneuroptera (Diplax and Termes). 

 The larvae resemble the pupae, and the latter only differ from the 

 adults in having wing-pads, i. e., undeveloped wings. In certain 

 genera the wings are almost undeveloped, as in Clothilla and 

 Atropos. The little book-louse or " death-watch," the name it is 

 known by in England, is a little dirty-white insect which is to be 

 FIG. 209. Clothilla seen rapidly running over dusty books, and in boxes or drawers 



pulsatoria. . -i -i i i 



ot insects, where it does considerable injury to specimens or books, 

 feeding upon the paper. In England it is said to make the ticking sound, like that 

 made by the death-tick beetle (Anobiuni), heard in walls of rooms, and certain popular 

 superstitions are connected with this insect. 



The family EMBID^E embraces but a few species of insects, and those very rare,, 

 inhabiting tropical countries, none of them occurring in the United States. They are 

 small insects, forming a connecting link between the white ants and fsocus ; they 

 are characterized by the linear, depressed body, with the head free from the thorax, 

 the wings equal in size, with few veins, and with three-jointed tarsi. The larvas are found 

 under stones, and are protected by a cocoon which they renew at each moulting of the 

 skin. One of the best known species is Embia savignyi of Westwood, which inhabits 

 Egypt. A species of embid (Olyntha, referred to Embia by McLachlan), is stated by 

 Dr. Hagen to occur in Cuba. Mr. J. Wood-Mason, who has recently studied these 

 forms in India, is of the opinion that they are true Orthoptera. 



The family TERMITID^E is perhaps the most interesting group of the order, whether 

 we take into account the structure, or the wonderful difference in the form and 

 habits of the various sets of individuals forming a colony. They are called white ants 

 from the general resemblance of the wingless forms to ants, and from their color, as well 

 as owing to the fact that they exist like ants in large numbers in mounds or " hills." 

 These insects had established themselves in the world long before the true ants 

 appeared, as their remains are found in the coal measures of Europe, while the true 

 ants did not appear in geological history until the tertiary period. Hence the white 

 ant is an old-fashioned form which has persistently held its own from the early geo- 

 logical ages until the present time, and this fact alone invests their history with a 

 peculiar interest. As it is, at the present day, white ants, though mainly tropical, are 

 wide-spread throughout the temperate regions of North and Soiith America, and 

 are sometimes extremely annoying from their great numbers and destructive habit 

 of eating out the interior of articles of furniture, such as chairs and tables, or the sills 

 of houses. For example, our common white ant (Termes flampes), while usually 

 running hidden galleries or mines in stumps or trunks of trees, often in a similar way 

 mines the roots of grape-vines, or enters the interior of timbers forming the sills of 

 houses, leaving but a shell. In the same way these insects in India enter houses by 

 subterranean passages, effect an entrance into the legs of tables and chairs, mine the 



