662 



CLASS IV. INSECTA. 



A labrum is also described. Meinert however holds, with much 

 appearance of reason, that the inner, protrusible tube is modified 

 from the epi- and hypo-pharynx.* As in the Mallophaga the 

 nervous system is much concentrated. There is but one family : 



Fam. 1. Pediculidae. With the characters of the Order. There are 

 six genera and about forty species of Lice, three of which Pediculus capitis, 

 P. vestimenti, and PMhirius inguinalis (Fig. 415) attack man. Many 

 authorities regard the first two as one species. They still form a terrible 

 scourge to armies in the field, but are far less common than in the middle 

 ages, when especially in the South of Europe most inns kept a lousing -room 

 or outhouse, described in many a Spanish novel. Monkeys suffer much 

 from a distinct genus Pedicinus, Seals are infested by Echinophthirius and 

 Elephants by Haematomyzus elephantis. The claw which terminates each 

 leg is said to be beautifully adapted in the various species to the cir- 

 cumference of the hairs of their respective hosts. 



Order 5. SIPHON AFTER A f (APHANIPTERA). 



Laterally flattened insects, without wings ; head small with 

 short stout antennae ; no neck ; eyes small or absent. 



The flattening of the body in the vertical, longitudinal plane 

 is confined to the flea amongst insects. The antennae have a 



A 



FIG. 416. a Pulex avium <J (after Taschenberg). A antenna ; Jf niaxillary[palp. b larva 



of Pulex irritans. 



peculiar insertion and are often placed in depressions ; there 

 seems to be no clypeus, the mandibles are piercing stylets with 

 saw-like edges, the maxillae bear long palps which project and 



* Meinert, Ent. Meddel, iii, p. 58, 1891. 



t Taschenberg, Die Flohe, 1880. Wagner, Home Soc. ent., xxiii, 1889, 

 p. 199. N. C. Rothschild, Nov. ZooL v, 1898, p. 533 and Rep. Thompson 

 Yates and Johnston Lab., vii, 1906, p. 1. 



