140 NATURAL HISTORY. 



and simple veins, of which the hinder pair are not folded in repose ; the front of the labium 

 shows only two lobes ; and the tarsi have two or three joints. The tribe includes two families. 



FAMILY IX. EMBIIDJE. 



This family consists of a small number of almost exclusively exotic species, which were originally 

 regarded as forming a somewhat aberrant portion of the preceding family. Their fore and hind 

 wings are narrow, and alike in form, size, and venation, the veins being parallel, or rather gently 

 divergent, and simple, except that in some species there are cross veinlets at light angles between 

 some of the veins towards the costal margin. In general form these insects have some resem- 

 blance to the Termites, but still more to the insects of the next family but one (Perlidtif), to which 

 they would seem to be most nearly related. They have a large free head, with a pair of small eyes 

 and a pair of beaded antennae, but no ocelli ; the prothorax is rather small and narrowed in front, 

 and the other two segments larger and about equal in size ; the legs are stout ; and the abdomen is 

 rather slender, of eight or nine segments, and terminated by a pair of two-jointed cerci. The maxillary 

 palpi have five, and the labial, when present, three joints. 



The species of this curious family are, as already stated, chiefly inhabitants of warm regions. 

 They are found in Africa up to the shores of the Mediterranean, in Persia and India, and in South 

 and Central America. None are yet recorded from Australia, but two species seem to occur in 

 Southern Europe, namely, Embia solieri in the south of France, and a species, probably identical with 

 the Egyptian E. savignyi, in Greece. Of their habits very little is known with certainty. The 

 perfect insects of Embia mauritanica have been described as living in company on tall herbage, upon 

 which they run with agility, but seem averse to make use of their wings. The larvae are found under 

 stones, where they reside in silken cases formed by themselves. M. Lucas says that they are car- 

 nivorous, and that the silken webs serve to capture insects upon which the larvae feed ; but great 

 doubt is thrown upon this statement by Mr. McLachlan, who has described a species (Oliyotoma 

 michaeli) the larvae of which had apparently injured the roots of an Indian orchid in a hothouse near 

 London, and were actually found to gnaw the roots when confined with them in a box. 



FAMILY X. PSOCID^E. 



This is a family of small insects also with simply veined wings, but differing from the preceding 

 in having the hind wings considerably smaller than the anterior pair. In some forms the wings are 

 wanting. They have a rather large head, with the forehead inflated, and bearing a pair of long 

 tapering antenrue, composed of from eight to about fifteen joints. The maxillary palpi are four-jointed, 

 the labium bears no palpi, and the anterior wings show a large horny stigma on their costal margin. 



The wings are fully developed in the great majority of the species, which also have three ocelli on 

 the crown of the head, and tarsi composed of two joints. They are found upon the trunks of trees, 

 old palings, walls, &c., in fact, in all those situations where lichens and mosses grow most luxuriantly, 

 and it is upon these and other low forms of vegetation that they probably feed, although they may 



diversify their diet by consuming the still more minute animals 

 that are to be met with in such places. They are active in their 

 movements, and generally appear in the perfect state towards 

 the end of the summer or in the early autumn. The females 

 deposit their eggs in small groups upon the under surface of 

 leaves, and cover them with a web of tine threads, which they 

 are said to spin from some part of the mouth. The known 

 species, which are not very numerous, are chiefly from the 

 temperate parts of the Old World. Besides the -.ringed species 

 CJECILIUB FBNESTKATUS. of p socu ^ and one or two a ni e d genera, the family includes 



some forms which are never known to acquire wings, and these 



are only too well known to collectors of insects. They live in books and among old damp papers, 

 whence they are often known as Book Lice; they are also among the "mites" which do so much mischief 

 to collections of insects and dried plants. They differ from the preceding in the absence of wings and 

 ocelli, and in having the tarsi three-jointed. The best-known species is called Atropos pulsatorius, 

 the specific name ref erring to an old belief that this feeble little creature was the " Death-watch." 



