146 ZOOLOGY, 
composed of a great number of small articulations; the oral organs are 
present, the palpi are conspicuous, and each side of the abdomen 
has a row of movable appendages, which Latreille considers false 
feet, and Gervais respiratory organs. The abdomen is composed of ten 
segments, and terminated by a number of multi-articulate threads, which 
vary in number according to the genera. The genus Machilus (pl. 77, 
figs. 81, 84) has a leaping spring like Podura, and a large compound eye 
formed by the fusion of the two which appear in other genera. The genus 
Lepisma (jigs. 82, 83) is found in houses in Europe and America, and from 
the silvery color of its scales, it is sometimes called sugar-fish. It runs 
rapidly, and is difficult to take without removing the scales. The common 
species is supposed to eat sugar, whence its name Lepisma saccharina. 
Orver 2. Anoptura. The order Anoplura (thus named by Macleay 
from the absence of locomotive caudal appendages) was also named 
Parasita by Latreille, on account of its parasitic habits, and Epizoa by 
Nitzsch, from its occurrence upon animals. In this order, which includes 
the lice, there are six feet, no wings, and two or four stemmata. 
Burmeister, as we have already seen, places the two families of which it is 
composed in separate orders, one, the Pediculide or lice, among the 
Hemiptera, and the Nirmide or bird lice among the Orthoptera, the former 
being haustellate and the latter mandibulate. The general structure and 
habits of the two families are very much alike, and’ we have seen that the 
best characters, as those afforded by the organs of respiration, are in certain 
cases not uniform throughout an order; so that in the present case the 
difference between the oral organs of the two families may be of no more 
account than the absence of special respiratory organs in some of the 
Crustacea. The head and thorax are distinct, the antennz are short, and 
composed of but few articulations ; the tarsi have but one articulation, ter- 
minating in a simple nail, sometimes doubled back, so as to form a claw 
adapted for holding. 
Fam. 1. Pediculide. The mouth is a small suctorial retractile rostrum 
placed beneath the head. The thorax is narrower than the abdomen, which 
is large, and with the segments (of which there are from seven to nine) 
distinct. ‘There are six pairs of spiracles. This family contains several 
genera, of which the best known is Pediculus. P. capites (pl. T7, jig. 
77, abc) infests the human head. The eyes are a black point on each side, 
the antennee have five articulations, and the general color is pale yellowish, 
with a dark line on each side. The skin is tough, and sufficiently translu- 
cent to exhibit the internal organs. Lice multiply rapidly with warmth 
and moisture. Leeuwenhoek, by keeping a male and female in his stocking, 
which he wore day and night, ascertained that one of them might increase 
to five thousand in eight weeks. They are found chiefly on children and 
dirty persons, more frequently upon the back of the head, and the use of 
hair powder is favorable to their increase. They are easily destroyed by 
-yarious mercurial ointments, or an infusion of Cocculus indicus. The 
louse which infests negroes is a distinct black species with a large flat head. 
Pediculus vestimenti (the clothes louse) is a second species which is found 
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