MALLOPHAGA 



347 



and bears near the front a chitinous sclerite corresponding with 

 another placed in the epipharynx. 



The prothorax in Mallophaga is a distinct division of the 

 body even when the meso- and meta-thorax appear to be part of 

 the abdomen. The mesothorax is frequently very small ; it and 

 the metathorax are sometimes intimately connected. In other 

 cases (Laemobothrium) the metathorax appears to differ from the 

 following abdominal segment only by having the third pair of 

 legs attached to it. In Trinoton (Fig. 214) the three thoracic 

 segments are well developed and distinct. The abdominal 

 segments visible, vary in number from eight to ten ; there is 

 sometimes a difference according to sex, the male having one 

 segment taken into the interior in connexion with the repro- 

 ductive organs. The legs have short, broad coxae and small 

 tarsi of one or two joints ; very rarely three joints are present ; 

 there are either one or two claws ; the legs with one claw being 

 adapted for clinging to or clutching 

 hairs. The front pair of legs is used 

 not for locomotion so much as for 

 grasping the food and bringing it 

 within the range of the mouth. Xo 

 trace of wings has been detected in 

 any species. 



The nervous system has been 

 examined by Giebel in Lipeurus 

 'bacillus; there is a supra- and an 

 infra-oesophageal ganglion, and three 

 thoracic, but no abdominal ganglia. 

 The supra-oesophageal is remarkably 

 small, in fact not larger than the 

 infra - oesophageal ; it consists evi- 

 dently of two conjoined halves. The 

 alimentary canal has a slender, elon- FlG . 2 i7.-Gan g iia of nervous sys- 

 gate oesophagus, dilated behind into a tem of Lipeurus bacillus. (After 



. 6 ' Giebel.) a, Cavity of head. 



crop ; this is frequently received be- 

 tween two cornua formed by the anterior part of the stomach, 

 which, except for these, is simply tubular in form, though some- 

 what narrower at the posterior extremity. In some forms 

 Philopterides the crop is of a very peculiar nature (Fig. 218), 

 forming an abrupt paunch separated from the stomach by the 



