RMBRYOLOGICAL METHODS. 



629. Hymenoptera. CARRIERS & BURGER (Nova Ada Acad. 

 Leop. Car., Ixix, 1897, p. 273) kill ova of CJialicodoma by 

 warming in water to 60 C., and fix in aqueous picric acid, 

 or alcohol of 70 per cent. 



PETRTJNKEWITSCH (Zool. Jahrl. Abth. Morph., xiv, 1901, 

 p. 576) fixes for twenty-four hours in his sublimate mixture, 

 and passes into alcohol of 70 per cent, with iodine. 



630. Orthoptera (PATTEN, Quart. Journ. Hie. Sci., 1884, p. 

 549). The ova or larva? (of Blattida) are placed in cold 

 water, which is gradually raised to 80 C. You leave off 

 heating as soon as the ova have become hard and white. 

 Pass very gradually through successive alcohols, beginning 

 with 20 per cent. 



WHEELER, (Journ. of Morph., iii, 1889, p. 292) dissects out 

 ovarian ova in salt solution and fixes in liquid of Perenyi 

 (fifteen minutes), then treats with alcohol, and stains with 

 borax-carmine. Laid eggs may be killed by Patten's method. 

 After heating, the two lips of the crista of the capsule may 

 be separated with fine forceps and pieces of the walls torn 

 away, and the eggs pushed out of the compartments formed 

 by their choria and hardened as desired. Good results are 

 also obtained by heating to 80 C. for ten minutes in 

 liquid of Kleinenberg, and preserving in 70 per cent, 

 alcohol. This causes the envelopes to dilate and stand off 

 from the surface of the egg, so that they can easily be 

 dissected away. 



HEYMONS (Zeit. wiss. Zool., liii, 1892, p. 434), for young 

 embryos, incises the cocoon at the end by which it adheres 

 in the body of the mother, brings it for two minutes into 

 water heated to 90 C., and opens in Flemining, in which 

 the embryo is dissected out. 



MORGAN (Amer. Natural., xxii, 1888, p. 357) puts ova of 

 Periplaneta for thirty minutes or an hour into ean de Javelle 

 diluted with 4 to 8 vols. of water and slightly warmed, which 

 softens the capsules. 



631. Coleoptera. HIRSCHLER (Zeit. wiss. Zool., xcii, 1909, p. 

 628) fixes ova of Donacia (after incising the chorion) for two 

 to three hours in equal parts of sublimate of 6 per cent, and 

 nitric acid of 3 per cent. 



