146 ZOOLOGY. 



composed of a great number of small articulations ; the oral organs are 

 j)resent, the palpi are cons^jicnous, 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 nmlti-articulate threads, which 

 vary in number according to the genera. The genus Machilus {pi. YT, 

 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 {figs. 82, 83) is found in houses in Europe and America, and from 

 the silverv color of its scales, it is sometimes called suo:ar-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. 



Oeder 2. Anoplura. Tiie 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 

 jS^itzsch, from its occun'ence 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 PedicuUdcn or lice, among the 

 JIe7nij)tera., and the Nirmidie or bird lice among the Orthoptera^ the former 

 being hanstellate 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 tlie 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 disthict, the antenna? 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. Pediculldai. Tlie 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 Pedioulus. P. capitis {pi. 77, fi.g. 

 77, a h c) infests the human head. The eyes are a black point on each side, 

 the antennae 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 

 various mercurial ointments, or an infusion of Coccidns mdicus. 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 

 350 



