Psoroptic Acariasis in Solipeds. 1 69 



tion to report the same to a government veterinary ofBcial for 

 diagnosis, and a penalty should be imposed in case of disobedi- 

 ence. In this case as in all other instances of dangerous infec- 

 tious disease the protection of the many must dominate over the 

 inconsiderate and selfish assertion of individual rights. 



PSOROPTIC ACARIASIS IN SOLIPEDS. DERMATO- 

 DECTIC (DERMATOCOPTIC) SCABIES. HUMID 

 MANGE. 



Psoroptes Communis v. equi : Long rostrum ; posterior pair of legs small, 

 without suckers ; male with two posterior marginal 5-bristled lobes ; in 

 female 3d pair of legs, without suckers. Accessory causes as for sarcoptes. 

 Vitality greater than in sarcoptes. Susceptible : Live only a short time on 

 other genera. P. of rabbit lives on horse. Symptoms : Extend more rap- 

 idly and are more venomous than sarcoptes. Preference for dorsal line, 

 poll to rump ; later the axilla, groin, inner sides of thighs, intermaxilla ■ 

 itching and lesions largely as in sarcoptes. Diagnosis easy, the acarus being 

 on the surface. Treatment : As for sarcoptes, but more promptly success- 

 ful. Prevention : As for sarcoptes. 



Essential Cause. Psoroptes Communis var. Equi. Pso- 

 roptes Longirostris. Lrong-nosed Psoroptes. With the 

 general characters of the psoroptes this is especially distinguished 

 by the great length of the rostrum, more than twice as long as 

 broad ; in the male by the dwarfed appearance of the posterior 

 pair of legs devoid of suckers, and the presence on the border be- 

 hind the two copulatory suckers, of two triangular, projecting, 

 marginal lobes, each bearing five bristles, the three central, ter- 

 minal ones being the longest and about equal ; in the female the 

 third pair of legs have no sucker, but each is terminated by two 

 long bristles, the fourth pair have suckers ; the pubescent female 

 has two tubercles near its posterior border which are received 

 into the copulatory suckers of the male ; the larva has the third 

 pair of legs provided with suckers. The male is about .48 mm. 

 and the ovigerous female about .65 mm. long. 



Accessory causes. These are the same as for sarcoptic 

 acariasis, only from the parasite living exclusively on the surface 

 and not beneath, it passes from horse to horse with much greater 

 readiness, and is by far the most common form of equine mange. 



