Hamicossus laevis sp. nov.

(Fig. 3A–B)

Diagnosis: As for genus.

Description: Head oval with a rostrum. Abdomen with at least 8 visible segments.

Forewing triangular with distinct CP and nodal line. Sc with several oblique veinlets, fused with stem of R+M at basal, and arising from R+M before R+M separating into R and M, and fusing with R again little after R1 arising from R. Rs simple. M four­branched and bifurcating into M1+2 and M3+4 little after point of R1 arising from R. M4 sharply flexed after arising from M3+4. Short crossvein r­m present between Rs and M1. Cu divided into CuA and CuP at base. CuA curved, joined with M by crossvein m­cua and also connected with M4 by long horizontal crossvein. CuA branched into CuA1 and CuA2. CuP single. Anal area with 1 visible vein. Nodal line traceable as indentation cross Sc+R and Rs to M1+2, along with latter to branching point of M, dividing discal cells into two parts, following stem CuA and CuA2, terminating at distal end of clavus. 2nd discal cell nearly rectangle.

Hind wing smaller than forewing, costal margin curved posteriorly, forming prominent indentation.

Body 21 mm long, 13 mm wide; forewing 36 mm long, 16 mm wide; hind wing 20 mm long, 14 mm wide.

Etymology: From the Latin ‘laevis’ = vein smooth, indicating the shape of crossvein m4­cua.

Material: The new species is established based on body with a pair of forewings and a pair of hind wings. Holotype: Body with wings compression, No.: CNU­H­NN2006095.

Horizon and locality: Jiulongshan Formation, Middle Jurassic, Daohugou Village, Shantou Township, Ningcheng County, Inner Mongolia, China.