153 



Pediculoides has been recorded in an earlier paper by this author. 

 The disease is so virulent that silkworms are killed by it within a few 

 hours of infection. This report describes investigations as to the 

 true origin of the disease and experiments as to whether it is caused by 

 mechanical action, interference with nutrition, or the presence of 

 bacteria or toxic substances introduced by the mite, especially the last 

 two, as being the most probable. Injections of the body fluid of 

 infected silkworms into healthy ones proved negative. Nothing was 

 revealed by microscopical examination, nor were any bacteria obtained 

 from cultivations on agar-agar. It is therefore concluded that the 

 disease is not due to bacterial or bacillary action. 



Experiments were then made with an extract from the larvae of 

 this mite in salt solution. Injections of this extract proved toxic to 

 silkworms of the fifth instar in periods varying from 23 to 63 hours. 

 The author is therefore of opinion that the disease is unquestionably 

 due to toxic substances contained in the body of the mite and this view 

 was confirmed by further experiments which showed that 0*50 gr. of a 

 1 per 100 solution of dead mites and 4 c.c. of physiological salt solution 

 (0"85 per cent.) is fatal to silkworms, while a 1 per 1,000 solution is 

 not so. It was further found that the extract lost its virulence when 

 kept at a temperature of 100° C. [212° F.] for five hours. The toxic 

 action of the virus also varies with the atmospheric conditions, death 

 taking place more. quickly when the temperature is high. 



This mite also attacks the human skin, causing dermatosis, with 

 symptoms of severe itching and reddish swellings with white centres. 

 In severe infestations the afiected part becomes swollen, and fever 

 occurs. 4:^ 



The mites are also found in abundance in grain, whether barley, 

 wheat or rye, and one case was observed in which the caterpillar of 

 a grain moth was infested with them. They are widely distributed 

 in Japan. 



Amaei (S.). Bakuriu chu no Tarsonemus Dani no Keitai. [The 

 Morphology of Tarsonemus found in Barley Grain.]— ^Sawgryo 

 ShiJcenjo Hokoku. [Report of the Sericultural Experiment Station.} 

 Tokyo, iii, no. 6, 16th September 1918, pp. 371-376, pi. xxix. 



A description is given of a mite, a species of Tarsonemus, found 

 in grains of barley, which has a close resemblance to the species of 

 Pediculoides infesting silkworms. Its morphology is described in 

 detail and the points distinguishing it from the latter species 

 are given. 



Chino (M.), Tento-mushi no Heni ni kuwansuru Kenkyu. [Researches 

 . on the Variation of the Coccinellid [Ptychanatis axyridis, Pall.).] — 

 Shinano Kyoiku [Education in Shinamo]^ Shinamo, Year 7, 

 October 1918, pp. 1-9, 9 figs. 



Though this paper mainly discusses the variation and inheritance 

 of the wiag- markings of Ptychanatis axyridis. Pall., some remarks 

 on the life-history of this Aphid-destroying Coccinellid are appended. 

 The eggs are usually laid in masses on the upper side of the leaf and 

 occasionally on branches or on the bark. They are spindle-shaped, 

 bemg pale yellow at first and orange-yellow later. They usually hatch 



(C662) B 



