and 50 cc. of the strained dung extract were then mixed in 100 cc. of 

 water. A decoction of swallow- wort (Chelidonium majiis) caused a 

 death-rate of 4 per cent, in Malacosoma neustria and of 44 per cent, of 

 in Vanessa urdcae. A decoction of chamomile {Matricaria discoidea) 

 proved quite inefEective. Henbane {Hyoscyamus niger) was responsible 

 lor a death-rate of 76 per cent, in M. neustria, of 45 per cent. 

 in V. vrticae, and 100 per cent, in Pteromis ribesii {Nematus ventricosus). 



A decoction of spurge {EujjJiorbia sp.) caused a death-rate of 38 per 

 cent, in M. neustria, which would probably have been higher, but for 

 the fact that 20 per cent, of the caterpillars pupated during the experi- 

 ment. A decoction of white hellebore {Veratrum album) gave in- 

 significant results, as also did a decoction of tomatoes {Lycopersicum 

 escidentum, L.) ; in the case of the last, the result, which is at variance 

 with statements of other authors as regards its effect on Pieris brassicae, 

 may probably be attributed to the weakness of the extract. Decoctions 

 of tobacco [Nicotiaiia rustica) and quassia {Qiuissia surinamensis) are 

 well known as contact poisons, and experiments on these lines also 

 showed that they are effective as stomach poisons. Tobacco decoction 

 prepared by boiling 1 lb. of tobacco in 3 gals, of water and diluting 

 the strained liquid in another 6 gals, of water, produced a death-rate 

 amongst caterpillars of P. brassicae as high as 62"5 per cent. Quassia 

 •lecoction (3 lb. of quassia in gals, of water boiled down to half 

 the original volume, strained and niLxed with 2 lb. of soft soap and, 

 before use, diluted in about 8 gals, of cold water) produced the same 

 high death-rate among the caterpillars of P. rapi and Barathra 

 {Mamestra) brassicae. Another experiment, in which the decoction 

 was not diluted with water before use, gave a still higher death-rate. 



Some experiments were also made with mineral insecticides. Acid 

 chromate of lead, about 2 oz. in 4 gals, of water, gave unsatisfactory 

 results on caterpillars of A. crataegi and M. neustria, though a stronger 

 solution of 2 oz. in 3 gals, gave varied results, the death-rate being 

 higher amongst caterpillars of M. neustria (32-40 per cent.) than among 

 those of P. brassicae (]2'5 per cent.). " Galiatzin," which is a new 

 commercial preparation, gave very poor results. Lead arsenate, both 

 conmiercial and home-made, gave excellent results, the death-rate 

 amongst caterpillars of M. neustria' being 100 per cent. A mixture of 

 common salt and lime, as recommended by Professor N. Kulagin 

 (3 parts by weight of salt and 2 parts of lime in 100 parts of water), gave 

 a death-rate of 34 per cent, amongst catei^pillars of P. brassicae and 

 deserves further attention. Paris green, which, according to some 

 authors, is ineffective against caterpillars of P. brassicae and is 

 insufficiently adhesive, caused a death-rate among these caterpillars 

 of 9ri per cent. To make it adhesive, soft soap (1 oz. of green, 1 oz. of 

 Ume, I lb. of soap in 6 or 7 gals, of water) should be used in preference 

 to molasses. White arsenic (7 lb. of arsenic boiled until dissolved 

 with 2 lb. of common soda, with 3-5 lb. of quick lime added 

 and boiled for another 1-2 hours, the whole being diluted with 180 gals, 

 of water) caused a death-rate of 80 per cent, among caterpillars of 

 A. crataegi. " Mortus," a new preparation of unknown composition, 

 but probably containing sodium arsenate, is very effective, and has 

 been introduced as a fungicide ; in the proportion of 1 lb. in about 

 145-150 gals, of water it proved an excellent remedy against cater- 

 pillars of M. neustria, resulting in a death-rate of 100 per cent. ; it 



