Japanagromyza tristella (Thomson, 1869)
This study of the male genitalia is necessary for reliable identification.
Wing length: 2.4 - 3 mm. Fore tibia with one lateral bristle, middle tibia with two bristles.
Hypandrium long and thin with very long hypandrial apodeme. Aedeagus with a peculiar coiled form.
Larvae were described by Kuroda, 1958 (as Melanagromyza spec., including first instar), Kato, 1961 as (Japanagromyza nawai Kato), Sasakawa, 1961 and Beri, 1971a (both as variihalterata).
Posterior spiracles large with three terminal branches of felt chamber which are secondarily branched. Mandibles with numerous fine mouth hooks, more than four on each mandible. The upper mouth hooks are slightly larger than the lower one.. The cephalopharyngeal skeleton widely corresponding to the general concept of the genus Japanagromyza. Facial mask with conspicuous facial sclerites.
Blotch miner on the upper surface of young leaves and leaflets respectively, normally with several larvae in each mine (1-5). There are two generations per year in Japan (Sasakawa, 1961). Several generations per year were also confirmed by other authors.
Glycine soja Sieb. and Zucc., Pueraria hirsuta Matsum., P. phaseoloides Benth., P. thunbergiana Benth. (= triloba Makino).
S. China, Taiwan, Formosa, Japan, Bismarck Archipelago, Indonesia: Java, Flores; Singapore; Malaya; Sri Lanka; Nepal; India (Spencer, 1973).
The species belong to the high number of insects feeding on soya, its contribution to yield reduction is not yet thoroughly investigated. Japanagromyza tristella may be of some local importance (Kato, 1961).