14 



AN INTRODUCTION TO ENTOMOLOGY 



CLASS PENTASTOMIDA 



The Pentastomids or Linguatulids 



The members of this class are degenerate, worm-like, parasitic 

 arthropods, which in the adult state have no appendages, except two pairs 

 of hooks near the mouth; the larva have two pairs of short legs. These 

 animals possess neither circulatory nor respiratory organs. The 

 reproductive organs of the male open a short distance behind the mouth; 

 those of the female near the caudal end of the body. 



The Pentastomida or pentastomids are worm-like creatures, whose 

 form has been greatly modified by their parasitic life. The adults 

 bear little resemblance to any other arthropods. Representatives of 

 three genera are known. These are Lingudtula in which the body is 

 fluke-like in form (Fig. 15) and superficially annulated; Porocephalus, 

 in which the body is cylindrical (Fig. 16) and ringed; and Reighdrdia, 

 which is devoid of annulations, and with poorly developed hooks and 



a mouth-armature. 



The arthropodan nature of these animals is 

 indicated by the form of the larvae, which although 

 greatly degenerate, are less so than the adults, 

 having two pairs of legs (Fig. 17). 



--OV 



Fig. 15. A pentasto- 

 mid, Linpuatula 

 tanioides, female at 

 the time of copula- 

 tion: h, hooks; oe, 

 oesophagus, rs, re- 

 ceptacula seminis, 

 one of which is still 

 empty; i, intestine; 

 ov, ovary.; va, vagina 

 (From Lang after 

 Leuckart). 



Fig. 1 6. A pentastomid, 

 Porocephalus annulatus; 

 a, ventral view of head, 

 greatly enlarged; b, 

 ventral view of animal, 

 slightly enlarged (After 

 Shipley). 



Fig. 17. A pentastomid, larva of 

 Porocephalus proboscideus, seen 

 from below, highly magnified: i, 

 boring anterior end; 2, first pair 

 of chitinous processes seen be- 

 tween the forks of the second pair; 

 3, ventral nerve ganglion; 4, ali- 

 mentary canal; 5, mouth; 6 and 

 7, gland cells (From Shipley after 

 Stiles). 



