Introduction io Animal Morphology. 3 go 



palp (Philopterus), or clavate, four-jointed, with (Liotheum) 

 or without a palp (Gyropus). This may be a sub-order of the 

 next. 



2. Rhynchota {Fahricius) — with or without wings ; mouth 

 suctorial ; labium elongated into a long, apparently jointed, 

 tube {vagifia), only open above at the base, where it is covered 

 by the opercular labrum. Within this the maxillae and man- 

 dibles are altered into sharp, protrusible, piercing setse ; 

 maxillary palps none ; labial palps merged into the vagina ; 

 eyes moderate, compound or simple ; the antennas are either 

 short, 2-3 jointed, and aristate, or long. When wings exist, 

 the fore pair are often, for at least half their extent, leathery 

 or horny, forming hemielytrcB or sheaths for the hinder pair. 

 The tarsus is usually 2-3 jointed ; the stigmata are ventral • 

 there is no crop ; a long, often trifid, stomach ; the intestine 

 is usually tortuous, with four Malpighian tubes ; there is no 

 bursa copulatrix (except in Cicada, which has a double re- 

 ceptaculum seminis) ; the larvae, at the first moult, show the 

 rudiments of the wings ; many of them have odorous glands 

 on the metathorax or abdomen ; they are mostly retrogressive 

 forms, living on plant or animal juices, and include three 

 sub-orders : — 



1. Pediculina {Burmeister) — lice, wingless, ametabolic, 

 with two ocelli and a sharp proboscis armed with recurved 

 hooks ; antennae thread-like, five-jointed ; thorax obscurely 

 segmented (Pediculus) ; extremely small in Phthirius ; para- 

 sites on mammalia. At least three species infest mankind : — 

 Pediculus capitis, the head-louse ; P. vestimenti, and P. 

 tabescentium, the louse which multiplies so rapidly in the 

 disease Phthiriasis, of which Herod, Sulla, Honorius (King 

 of the Vandals), the Emperor Arnulf, Philip II., &c., died. 

 Haematopinus is a common pig- and cattle-parasite. 



2. Homoptera {Latreille) — wings two or four, equal, lying 

 straight, and imbricated on each other when at rest ; often 

 absent in the females ; mouth usually turned back ; prothorax 

 short, and the three thoracic rings more or less united ; eyes 

 compound, with ocelli between them. Here belong the fol- 

 lowing families : — i . Coccidae — mostly tropical, phytophagous ; 

 antennae six- or more jointed ; proboscis, and often hind 



