439 



Harukawa (C.) & Yagi (N.). The Serpentine Leaf-Miner of the 

 Peach, a species of Lyonetia. — Berichte Ohara Inst, landwirtschftl, 

 Forsclmngen, Kuraschiki, i, no. 3, 1918, pp. 335-;548, 1 plate. 

 [Received 21st August 1919.] 



One of the important peach pests in Japan is a leaf-miner first 

 described by Sasalci in 1903, of which the complete life-history 

 was worked out in 1909 by Kuwana and Takachiho, the name, Lyonetia 

 chrkella, L., being used in their results published in 1911. The 

 Japanese serpentine leaf-miner does not, however, seem to be the same 

 species as that described by European authors, though it is very 

 closely allied to it. 



Observations on it made since the summer of 1915 are here recorded. 

 This moth occurs in various provinces, but its presence in Hokkaido is 

 doubtful, although an apple pest occurs there which is probably 

 identical with L. clerkella. There appear to be 7 generations a year, 

 the last probably being a partial one. The length of the life-cycle 

 varies from 16 to 32 days according to the season. The length of the 

 egg-stage is 2-8 days, of the larval 7-16, of the pupal 3-9, and of the 

 adult 4-7. The egg, larva, pupa and adult are described. The 

 moth rests on the under-surface of the leaf during the day, and its 

 flight is so slow that it can be captured by hand. Oviposition takes 

 place at night, the egg being laid in the leaf-tissue. The number of 

 eggfci varied from 37 to 132 in the experiments. The food-plants of 

 the larva are the peach and sand-cherry, the former being preferred. 

 It has not been observed on apple or cherr3\ The eggs are laid singly. 

 The full-grown larva is 5-6 mm. in length and remains until mature 

 in the mine, where it moults twice. On leaving the mine it begins to 

 spin its cocoon. Though the egg is introduced into the leaf-tissue 

 from the lower surface of the leaf it is laid just under the upper epider- 

 mis. The mine is serpentine in outline. The mature larva leaves the 

 mine by cutting open the upper epidermis, and usually spins its cocoon 

 on the under-side of the leaf. The structure of the cocoon and the 

 method of spinning are as in L. clerkella. This miner hibernates in 

 Japan in the adult stage, passing the winter in warm, protected 

 places. A very brief description is given of four Chalcid parasites of 

 the larva reared in August and September. A Braconid was reared 

 from the pupae. 



The paper concludes with a comparison of the characters, habits, 

 food-plants, etc., of this species and of L. clerkella. 



Yagi (N.). Preliminary Note on the Lif^-Period of the Bulb Mite, 



Rhizoglyphus echinopus. — Berichte Ohara Inst, latidwirtschftl. 

 Forschungen, Kuraschiki, i, no. 3, 1918, pp. 349-360, 8 figs, 1 

 plate. [Received 21st August 1919.] 



The present paper deals principally with the external morphology 

 of each stage found during the summer of the l^ulb-mite, Rhizoglyphus 

 echinopus. This mite moults twice, and the duration of one generation 

 is about 10 days in August, 15 in July, and 20 in June. Temperature 

 is the chief factor in this variation and has an important effect on the 

 embryonic development. The experiments made seem to show that 



