14 



AN INTRODUCTION TO ENTOMOLOGY 



Class PENTASTOMIDA 

 The Pentastomids or Linguatulids 

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

 q/fthropods , which in the adidt state have no appendages, except two pairs 

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

 animals possess neither circidatory nor respiratory organs. The 

 reproductive organs of t!ie 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 Re igJidrdia, 

 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). 



Fig. 15. — A pertasto- 

 mid, I.ini^ uattila 

 t a ni oilers, f irnle at 

 the time of copula- 

 tion: //, hooks; oe, 

 cesopliaur.s, rs. re- 

 ceptanila seniini?, 

 one of which is still 

 empty; i, ir.testine; 

 07', ovary; fa, vagina 

 (From Lang after 

 Leuckart), 



Fig. 1 6. — A pentastomid, 

 Porocephalus annulaius; 

 a, ventral view of head, 

 greatly enlarged; b, 

 ventral view of animal, 

 slighlly enlarged (After 

 Shipley). 



Fig. 17 — A pentastomid, larva of 

 Poroi fpJialus proboscidens, seen 

 from below, highly magnified: I, 

 boring anterior end; 2, first pair 

 of chitinons processes seen be- 

 tween the fo'ks of the second pair; 

 3, ventral nerve ganglion; 4, ali- 

 mentary canal, 5, mouth; 6 anc 

 7, gland cells (From Shipley after 

 Stiles). 



