MUSCACE^. 



[ 523 ] 



MUSCLE. 



wliich have been foimed into new genera, 

 we may mention : 



Miisca domestica, L., common house-fly. 

 Third joint of antennie thrice the length of 

 the second ; style plumose, eyes reddish 

 brown, front of head white, the rest black ; 

 thorax blackish grey witli four longitudinal 

 black bands, abdomen blackish bi'own above, 

 with blackish elongated spots, pale yellow- 

 ish brown beneath. 



M. carnaria, L. (Sarcophac/a, Meigen), 

 the flesh-fly. Antennae feathery ; head 

 golden-yellow in front, eyes reddish : thorax 

 grey, with black longitudinal lines; abdomen 

 black, with four square white spots on each 

 segment ; all the body strewed with black 

 hairs. Viviparous, 1-2" long. 



M. C(ssar, L. (Lucilia, Donov.). No 

 spots, abdomen green, with a metallic lustre. 



jM. vomitoria, L. (Callip/ioi-a, Donov.), 

 bluebottle or blow-fly. Head yeUowish, 

 golden or white, eyes brown ; thorax black ; 

 abdomen shining blue with black stripes 

 and long black hairs. 



The larvae are known as gentles. The 

 ova or larvae are deposited upon animal or 

 vegetable substances, mostly in a state of 

 decay, upon which they live. 



Several parts of the species of Musca are 

 of general microscopic interest, — as the 



f)roboscis (PI. 3.3. fig. 29) with its two fleshy 

 obes (c), kept expanded by a beautiful and 

 elastic framework of modified tracheae; ; the 

 setae or lancets (b), which are modified 

 maxilla}, sometimes rudimentary, with theii* 

 palpi (a) at the base ; the remarkable an- 

 tennae (PI. 33. fig. 20) ; the elegant tarsus 

 (PL 34. tig. 7 a), with its terminal spine, 

 pulvilli (figs. 7, 8 & 9) and claws ; and the 

 rudimentary wings or halteres (Insects, 

 p. 432). 



Musca pumilionis {Chlorops, Meig.) de- 

 posits its eggs in the j'oung wheat-grain, 

 which is consumed and destroyed by the 

 larvae. 



Many other members of allied femilies of 

 Diptera, commonly known also as flies, are 

 of microscopic interest, on account of their 

 oral setas or lancet-hke organs. 



BiBL. Westwood, Infr.; Macquart, Ins. 

 Dipt. ; Meigen, Syst. ziceifli'ig. Insect. ; Keller, 

 Stuhenjliege ; Sufiblk, Mn. Mic. Jn. i. 331 ; 

 Lowne, on the Bloiv-Jly. 



MUSCA'CE^. See Mosses. 



MUSCARDINE. — A disease in silk- 

 worms, in wliich the whole of the sebaceous 

 matter is exhausted, and the blood greatly 

 altered, by a species of mould, Botrytis 



bassiana, which is perhaps too near Botrytis 

 dijfusa, Grev. A few of the spores placed 

 on the back of a liealthy silkworm are 

 sufficient to impregnate the whole body. 

 It takes its name from the resemblance of 

 the diseased caterpillar to a pecuhar kind 

 of pastile. 



BiBL. Balsamo, Gaz. de Milan, 1835; 

 Bibl. If. xxix. 183o; Robin, Veg. Par. 5G0; 

 Guerin, Seric. 1849, 1850, 1851. 



MUSCLE. — Muscular tissue forms the 

 greater portion of the flesh of animals. 



It occurs in two principal forms ; one of 

 which is termed organic, unstriated, or 

 unstriped muscle ; the other, voluntary, 

 striated, or striped muscle. 



Unstriated muscle. — This consists of more 

 or less elongated, somewhat spindle-shaped, 

 narrow fibres (p. 74, fig. 35), having the 

 import of cells, and hence often called fibre- 

 cells ; they are, however, solid. Each con- 

 tains an elongated nucleus, brought to ligh? 

 by acetic acid, and exhibiting a reticulai; 

 appearance. The fibres are of variably 

 length (from about 1-580 to 1-2-50"), and 

 1-5000 to 1-3500" in diameter. They ofte, 

 appear longitudinally fibrous within ; and 

 the cell -wall is transversely wrinkledv 

 They sometimes exist singly in the midst 

 of connective tissue ; at others they are 

 united into rounded or flattened bundles, 

 and surrounded by an imperfect kind of 

 sarcolemma, composed of connective tissue 

 with elastic fibres. 



Eig. 498. 



Unstriated muscular fibres from the CB=iophagus of a 

 pig, after treatment with dilute nitric acid. 

 Magnified 10 diameters. 



They occur most abundantly in the hol- 

 low viscera, as the stomach, the intestines 

 the bladder, and the uterus ; but they also 

 exist in other situations, as the spleen. 



