TRUE ORTHOPTERA 3169 



which is attached to one of the hinder segments, is usually turned forward and held 

 in position under the body; when released, it springs back, striking the surface of 

 support, and causes the insect to bound up into the air. These little insects are to 

 be found commonly enough under flower pots, leaves, and stones, or under the 

 bark of trees and in other such situations. They may sometimes be seen collected 

 together in great numbers, and spread over the surface of the ground like a layer 

 of powder. Some species, such as Podurca aquatica, may frequently be seen floating 

 in patches on pools of water, and by striking 

 their tails against the surface of the water, they can 

 spring up into the air just as readil} 7 as others do 

 from the ground. Desoria gladalis is an interest- 

 ing species, found in Alpine regions, where it is 



often to be met with on the surface of the ice. Desoria gladalis. 



.,.,_.. N . (Greatly enlarged.) 



The bristle tails (Thysanura proper) form but a 



small number of genera, some of which are very remarkable in having a series of 

 small rudimentary legs on each side of the abdomen in addition to the ordinary six 

 legs borne by the thorax. In all the genera the antennae are formed of a large 

 number of joints; and the abdomen shows ten distinct segments, and, except in the 

 genus Japyx, carries at the end two or three long jointed tails. Japyx has instead 

 a pair of short pincers like an earwig. The little silver fish (Lepisma saccharina) 

 is one of the best-known insects belonging to this suborder. Found very often in 

 damp corners in houses, among old books or papers, it may be recognized by the 

 silvery scales covering its body, and by its three bristle-like tails, of which the 

 middle one is the longest. It feeds on the paste in the binding of books, and 

 on sugary and starchy substances generally, though it is credited also with eating 

 paper and linen. Thermophila furnorum is a species which lives in bakehouses, 

 where, as its name implies, it is often found in the ovens. 



Machilis is one of the genera in which the abdomen is provided with rudi- 

 mentary legs in the form of small cylindrical appendages, each of which is accom- 

 panied by two small protrusible sac-like organs. An appendage similar to those on 

 the abdomen is attached to each of the coxae of the two hinder pairs of legs. The 

 body, covered over with scales, is arched up in the middle, as in Lepisma, and 

 carries three tails. The eyes are large and faceted ; and the palpi are long, those of 

 the maxillae looking like a second pair of antennae. Two species of this genus are 

 found in Great Britain; one being common about rocks at the seaside, while the 

 other is to be met with under stones in different parts of the country. Campodea 

 staphylinus, the last insect we have to mention, is a pale, soft-bodied little creature, 

 which is common almost everywhere under stones and in loose garden soil. It runs 

 actively, and has two very long tails which it sticks up in the air or turns forward 

 over its body. It has no eyes; the antennae are shorter than the tails and of equal 



thickness throughout; and the abdomen has seven pairs of rudimentary appendages. 

 199 



