Physiology of Hcematopinus tenuirostris, Barm. 79 



Thus Piaget's doubts are got rid of. It remains only to 

 examine into a remark of G-iebel's. " If Denny's figure is 

 accurate," says he *, " this species is variable ; for it [the 

 figure] represents the head less pointed, the thorax longer, 

 the first pair of legs much stronger, and the abdomen less 

 perfectly spindle-shaped than is the case in our specimens." 

 These differences undoubtedly exist in the figure ; and to 

 this must be added that Giebel figures ten abdominal segments, 

 while Denny represents only eight Nevertheless I am of 

 opinion that we have not to do here with a variable species, 

 but that, by the inaccuracy of both the figures, the dissimi- 

 larity has been made to appear greater. If we were to assume, 

 from the figures, that this species varies, we must do the same 

 with many other species which have shared the fate of 

 topinus tenuirostris in the matter of figuring. 



Ilcem 



Place in the System, Name, Occurrence, Remedies. 



As regards the systematic position of Hcematopinus tenui- 

 rostris we may speak briefly as follows: — H. tenuirostris 

 belongs to the genus Hcematopinus , established by Leach, and 

 now containing about twenty species, which, again, is referred 

 to the great family of the Pediculiche or true Lice. The fol- 

 lowing Table, derived from Piaget f , may serve to characterize 

 its position in the family Pediculidae : — 



Pediculid^b. 



3. 



1. Antennae with 5 joints 



Antennae with less than 5 joint3 2. 



2. Antennae three-jointed Pedicmiis, Gerv. 



Antennae four-jointed Echinophthirius, Gerv 



3. Legs with two unequal claws ; head cylindri- 



cal (tubular) Hcematomijzus, Piag. 



Legs with one claw; head rounded or longish. 4. 



4. Abdomen with 6 segments with lateral dilata- 



tions. Its second segment with 3 closely 



approximated stigmata Phthiriits, Leach. 



Abdomen with 7-9 segments, with or without 

 lateral dilatations. Second segment with a 

 single stigma 5. 



5. Head narrowed into a neck before its insertion 



into the thorax. Abdomen with 7-8 seg- 

 ments. Tibia with a distinct thumb Pedicidus, Leach. 



Head narrowed insensibly into the thorax. 

 Abdomen with 8-9 segments. Tibia simply 

 elevated at the inner angle Hcematopinus, Leach. 



All the species of the genus Hcematopinus are parasitic 

 upon mammals. 



• 



IS, p. 43. t Loc. cit. p. 618. 



