CHAPTER XXV. 287 



hours in equal parts of sublimate of 6 per cent, and nitric acid of 

 3 per cent. 



GATENBY (Quart. Journ. Mic. Sci., 1917) for Donacia uses 

 Petrunkewitsch or picro-nitric. In the latter case the chorion 

 must be incised. 



SALING (Dissert. Marburg, 1906, p. 10) fixes ova of Tenebrio for 

 about two minutes in a hot mixture of 40 parts of alcohol of 96 per 

 cent., 4 of nitric acid, and 50 of saturated aqueous sublimate ; or 

 for three minutes in a hot mixture of 1 part of formol with 3 of water. 



KARAWAIEW (Bid. Centralb., xix, 1899, p. 124) kills larvae of 

 Anobium in hot water, freezes them with ether spray, cuts away a 

 lateral strip, lets them thaw, and puts for twenty-four hours into 

 picro-sulphuric acid. 



631. Phalangida. The ova of Phalangium opilio possess a chorion 

 covered with yellow corpuscles that render them opaque. BALBIANI 

 puts them into \vater with a few drops of caustic potash, and raises 

 to boiling point. The ova are then laid on filter paper, and the 

 chorion removed by rubbing with a camel's hair brush, the vitelline 

 membrane remaining intact, so that the embryo can be studied 

 through it. 



HENKING'S method (Zeit. wiss. Zool., xlv, 1886, p. 86). Fix with 

 boiling water or Flemming. Preserve the ova in 90 per cent, 

 alcohol. To open the chorion, bring them back into 70 per cent, 

 alcohol, which causes them to swell up so that the chorion can easily 

 be pierced with needles, and the ovum turned out. 



632. Araneida. KISHINOUYE (Journ. Coll. Sci. Imp. Univ. 

 Japan, iv, 1891, p. 55 ; Zeit. wiss. Mik., ix, 1892, p. 215) fixes in 

 water warmed to 70 or 80 C., puts into 70 per cent, alcohol, and 

 after twenty-four hours therein pierces the membranes and passes 

 through stronger alcohol. 



See also LOGY, Bull. Mus. Comp. Zool. Harvard, xii, 3, 1886. 

 Fix by hot water. The liquid of Perenyi may also be used ; it has 

 the advantage of not making ihe yolk so granular. 



MONTGOMERY (Journ. Morph., xx, 1909, p. 628) fix.es ova of 

 Theridium for one or two hours in Carnoy & Lebrun's mixture. 



LAMBERT (ibid., p. 420) fixes ova of Epeira in picro-sulphuric acid 

 warmed to 70 or 80 C. 



PURCELL (Quart. Journ. Micr. Sci., liv, 1909, p. 7) fixes ova of 

 Atta in boiling saturated sol. of sublimate in alcohol of 70 per cent. 



HAMBURGER (Zeit. wiss. Zool., xcvi, 1910, p. 3) fixes ova of 

 Argyroneta in Gilson's mixture. 



