DB. JOHNSTON ON THE ACARIDBS OF BEBWIOKSHIRB. 291 



Dogs, Chickens, Calves, and Horses, and not in the singular 

 number • yet never could find the least disturbance ensua 

 There must be therefore other causes enquired of the sudden 

 death and swelling of cattle ; and perhaps this insect is mis- 

 taken, and unjustly accused for some other. For some there 

 are which from elder times have been observed pernicious 

 unto cattle, as the Buprestis or Burstcow, the Pityocampe or 

 Eruca Pinuum, by Bioscorides, Galen and Otitis, the Staphi- 

 linus described hj Aristotle and others, or those red Phalan- 

 gious Spiders like Cantharides mentioned by Muffetus. Now, 

 although the animal may be mistaken, and the opinion also 

 false, yet in the ground and reason which makes men most 

 to doubt the verity hereof, there may be truth enough, that 

 is, the inconsiderable quantity of this Insect. For that a 

 poison cannot destroy in so small a bulk, we have no reason 

 to affirm. For if, as Leo Africanus reporteth, the tenth part 

 of a grain of the poison of Nuhia^ will despatch a man in two 

 hours ; if the bite of a viper and sting of a scorpion is not 

 conceived to impart so much ; if the bite of an Asp'will kill 

 within an hour, yet the impression scarce visible, and the 

 poison communicated not ponderable, we cannot as impossi- 

 ble reject this way of destruction, or deny the power of death 

 in so narrow a circumscription." — Bk. iii. p. 144-5. 



A Trombidium, a native of Guinea and Surinam, is em- 

 ployed as a dye ; " and," say Kirby and Spence, " it would be 

 worth while to try whether our T. holosericeum, so ren^ark- 

 able for the dazzling brilliancy of its crimson, and the beau- 

 tiful velvet texture of its down, which seems nearly related 

 to T. tinctorium, would not also afford a valuable tincture." 

 — Introd. Entom. i. p. 325. — The experiment is not worth 

 the trial. The insect is, indeed, not uncommon, yet the ex- 

 pense of collecting a sufficiency of it for making the experi- 

 ment would render any dye that might result valuable only 

 as a costly rarity. 



8. Leptus phalangii. 



Leptus phalangii. Leach in Edin. Encyclop. vii. 413. — 

 Acarus phalangii, Turt, Gmel. iii. 705. 8tew. Elem. ii. 323. 



Desc. Mite ovato-ventricose, of a uniform scarlet colour, 

 glossy. Body convex dorsally, rounded at both ends, rather 

 widest behind, even, covered with scattered short stiff 



