43 



SuperfamUy DEMODECOIDEA 



The hair-follicle mites — Very small, abdomen annulate, elongated, 



Demodex folliculorum, very common in the sebaceous glands 

 and hair follicles of man, usually with no ill results. A variety of the 

 same species on dogs gives rise to a very serious disease, demodecic 

 scabies. 



Description— Very small, 300-380/^ x 45/^, elongate, veriform, 

 with eight short 3-jointed legs and in front a short, median, sucking 

 rostrum. Abdomen tapering transversely striated and rounded at 

 the tip. 



Life history and habits — Deposit fusiform eggs, 70-90/x x , 25/^. 

 Multiplies very slowly ; hexapod larva, two nymphal stages. Mites 

 migrate over the skin to enter new glands. 



Class HEXAPODA 



(True Insects) 



Review the characteristics of the four orders discussed, as given 

 on page 14. 



Order MALLOPHAGA 



Includes all biting lice infesting birds and mammals. Illustrated 

 by: 



Menopon pallidum, the common hen louse. Responsible for 

 much loss to poultrymen, through reduced vitality and even death 

 of birds, and failure to incubate eggs properly. 



Description — Elongate oval, very flat, pale yellow body 1-1.5 mm. 

 long. Head triangular, semilunate, antennae 4-jointed, mouth 

 parts fitted for biting. 



Life history and habits — Eggs laid at base of feathers, especially 

 around the vent, hatching in six to ten days. Nymphs molt five or 

 six times. Lice very active; unlike the chicken mite, they remain 

 on the host and die soon after its death. Accounts of their occurrence 

 on horses confused with cases of the mite or of other species of biting 

 lice. The lice spread from bird to bird by infested mother hen, cock- 

 birds and to a less extent, by infested nests, etc. 



Methods of combatting — Roomy, dry, and sunny dust baths. 

 Various dusting machines for treating individual birds are on the 



