Abstract: This paper describes a new species of the genus Matsucoccus, collected from Pinus sylvestris var. mongolica at Tahe virgin forest in Heilongjiang province in June, 1980.Matsucoccus dahuriensis Hu et Hu sp. nov.Adult female mounted specimens enlongate evoid, length 3.7—4.3mm; greatest width 0.18—0.19mm. Mouthparts wanting. Antennae 9—segmented, with pairs of sensory spines on segments 6th to 9th inclusive. Eyes small. Nine pairs of spiracles, two thoracic and seven abdominal. Thoracic spiracles 0.25—0.028mm in diameter, the 1st abdominal spiracles 0.010—0.015mm and 7th abdominal spiracles 0.008—0.013mm. In adjacent to the thoracic and abdominal spiracles each with a small prominence. Dorsal cicatrices 0.006—0.010mm, in 4 transverse bands on the dorsum of 3rd to 6th abdominal segments, total mumber 91—131. Multilocular disk pores 37—51 in number, 0.013—0.015mm in diameter, with peripherical loculi 10—12 in number.Locality:Tahe Bureau of Forestry in Heilongjiang province of China. 20. June. 1980.This new species is closely related to Matsucoccus pine (Green) and M. insignis Borchs.,but can be separated from the latter in the follwing table:The holotype and one paratype were preserved in North-Eastern College of Forestry and 2 paratypes in Shanghai Institute of Entomology, Academia Sinica.