312 CHAPTER XXV. 



Baling [Dissert. Marhitrg, 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 satui'ated 

 aqueous sublimate ; or for 3 minutes in a hot mixture of 1 

 part of formol with 3 of water. 



Kaeawaiew {Biol. Gentralb., xix, 1899, p. 124) kills larvae 

 of Aiwbium in hot water, freezes them with ether spray, cuts 

 away a lateral strip, lets them thaw, and jDuts for 24 hours 

 into picro-sulphuric acid. 



633. Phalangida. — The ova of Plalmigium opilio possess a 

 chorion covered with yellow corpuscles that render them 

 opaque. Balbiani puts them into water 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. u'iss. 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. 



633. Araneida. — Kishinouye {Journ. Coll. Sci. Imp. Univ. 

 Japan, \Y, 1891, p. 5-5; Zdt. wiss. Mil:, 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 Locy, Bull. Miii. 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 the yolk so 

 granular. 



Montgomery [Journ. Morph., xx, 1909, p. 628) fixes ova 

 of Theridium for 1 or 2 hours in Carnoy & Lebrun's mixture. 



Lambert [ibid., p. 420) fixes ova of Epeira in picro-sul- 

 phuric acid warmed to 70° or 80° 0. 



PuRCELL [Quart. Journ. Micr. Sci., liv, 1909, p. 7) fixes 

 ova of Atta in boiling saturated sol. of sublimate iu alcohol 

 of 70 per cent. 



