The micrographic dictionary : a guide to the examination and investigation of the structure and nature of microscopic objects / by J.W. Griffith and Arthur Henfrey.

Griffith, J. W. (John William), 1819?-1901.

Date:: 1860

Credit: The micrographic dictionary : a guide to the examination and investigation of the structure and nature of microscopic objects / by J.W. Griffith and Arthur Henfrey. Source: Wellcome Collection.

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ACAEINA. thorax distinct from the ringed abdomen; legs terminated by 4 or 6 very minute claws. ACAEINA.—An order of AuAcmsiTDA. ACAEUS, Linn.—A genus of Ai’achnida, of the Order Acarina, and family Acarea (see Ahachioda and Acabea). The palpi adherent to the labium, the perfect legs, and the transverse furrow di- stinguish the genus. 1. Ac. domesticus (PI. 2. iig. 1), the com- mon Cheese-mite. Body oval, soft, whitish, turgid and furnished with long feathery hairs (&). The transverse fuiTow (e) occurs at about the anterior foiu'th of the body, and another is seen between the head and the part corresponding to the thorax. The head is susceptible of elevation and depres- sion. In its natural state it appears conical (d), and is frimished with two large mandi- bles ; these consist of a soft retractile basal joint (e), and a second dilated, non-retrac- tile joint (/) resembling the fixed claw of a lobster, and a moveable piece (/*) working against the latter. The two last pieces are toothed where in contact with each other. These mandibles can be advanced separately or together, and be separated or approxi- mated. When in a state of repose, they form as it were a roof above the labium. The la- bium (y) is quadrilateral, elongated, notched at the end, thin anteriorly and in the middle, and consolidated laterally with the palpi, which are 4 or 5-jointed Qih). The legs are reddish, inserted in two separate groups, but not very far distant as in Sarcoptes. The anterior pair of legs are remarkable for their size in the male, which is smaller and more active than the female; the third pair are the shortest and smallest; the third joint or femur is larger and longer than those next it; the sixth joint is long and thin; the seventh joint is furnished with a cordiform membranous cai-uncle, and a single simple claw or hook; rostrum and legs reddish. This species is viviparous and oviparous, and the eggs very numerous. These mites are very abundant upon old cheese, the powder of which entirdy con- sists of them, with their eggs and excrement. 2. Ac. longior. Body oblongo-ovate. Found upon Gruyere and Dutch cheese (PI. 2. fig. 2). 3. Ac. hicaudatm. Abdomen fm-nished with two pediform tubercles, beneath the base of each of which is a stigma. Found upon the feathers of an ostrich. 4. Ac. farincs. Found in bad flour. DeGeer, Mhn. mi. p. 97. pi. 15. fig. 16. 6. Ac. destructor. Somewhat resembles Ac. domesticus, but said to differ in not having the rostrum and the reddish legs, and in having long black hairs. It feeds upon the contents of entomological cabinets, especially buttei-flies. Schrank, Enum. Ins. Austrice, sp. 1057; Lyonet, Mem. Mus. xviii. p. 284. pi. 12. fig. 10-12. There is another Acarus which well de- serves the name of destructor, from its de- structive effects upon dried insects; it dif- fers from the Ac. domesticus only in having a more strongly marked fuiTow, in the legs being shorter, and the two foremost pairs being somewhat more widely separated at their origin; the sixth joint is particularly short. 6. Ac. lactis. Found upon preserved cream. Fabricius, Spec. Ins. ii. 490. 7. Ac. Dysenteric. Nyander, Amcnit. Acad. V. p. 97; Linn. Gmel. p. 2929. Found in the dejections of dysentery; also in old casks. 8. Ac. passerinus. Found upon young birds. DeGeer, vol. vii. 139. Ac. chelopus, Herm. Mem. Apterol. p. 82. pi. 3. fig. 7. 9. Ac. passularum. With two very long buccal bristles; it lives upon dried figs, and other saccharine fruits. liering. Nova Acta Nat. Curios, xviii. p. 618. pi. 46. f. 14, 16. 10. Acarus phimiger, Koch, Deutschl. Crust., &c. fasc. 5. pi. 16, is said to have feathery hairs; but this is probably the case in all the Acari, and certainly in many of them (PI. 2. fig. 1 b). Probably in Ac. plumiger this supposed peculiarity is distinguishable with a low power, xmder which these animals have been usually ex- amined. Some doubtful species have been formed into new genera, which may find place here. a. Glyciphagus (Hering). Body soft, not divided into two parts by a transverse line or furrow; legs perfect, -with acetabula. 11. A. {GL) prunomm. Foimd on dried plums. 'H.elms, Nova Acta Nat. ft<n‘os. xviii. p. 619. pi. 45. f. 16-17. 12. A. (Gl.) hippopodos. Body as broad as long, very acute anteriorly, entirely co- vered with short hairs; a minute projection at the end of the abdomen. Found upon the crusts of ulcers on horses’ feet. Henng, Nov. Act. Nat. Curios, xviii. 607. An unde- scribed Acarus has also been mentioned as occmTing upon the feet of sheep affected with the canker. Grognier, Zool. v6Ur. p. 233. 13. A. (Gl.) cursor. Found in the fea-

The micrographic dictionary : a guide to the examination and investigation of the structure and nature of microscopic objects / by J.W. Griffith and Arthur Henfrey.

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