Abstract: In China，in recent years，a kind of parasitic wasp has been used in controlling some long horned beetles infesting China fir or poplar trees．The scientific name of this wasp has not yet been identified．In the last months we were worMng on the naming and classification of some wasps parasitic on long horned beetles，and found the above mentioned wasp to be a new species belonging to the genus Sceleroderma，Bethylidae．The following is its descriptions．Scleroderma guani sp．n．．Female(apterous)：Length 3.5mm．Antennae yellow with the basal 2/3 of scapes yellowish brown．Head brown with eyes black and clypeus and mandibles except for extremes reddish brown．Thorax reddish browll with anterior margin of mesonotum brown．Abdomen brownish black with the last two segments paler．Legs yellowish brown but sides of femora with black stripes and tarsi yellow．First 4 antennal segments in the ratio of about 18：6:3:2，all the segments slightly wider than its Iong except the 1st，2nd and the last segments．Head almost square，WH 0.9×LH；WF 1.7×HE；distance from eye tops to vertex crest about 1.6×HE．Clypeus with a fairly round emargination and a V-shaped median carina．Mandibles with 3 apical teeth distinctly．(figs．1)．Female(Mate)：Length 3.2mm．Body blackish brown．Antennae yellowish brown with the basal 2/3 of stapes brown；clypeus and mandibles except for extremes reddish brown；metanotum with two large yellowish brown markings; legs brown with femora，apical margins of tibiae，and tarsi yellow．Wings hyaline，with a single closed cell; veins yellow．First 4 antennal segments in the ratio of about 5:2:1.5:1；transverse median vein of forewing 1.5×basal vein．Tibiae and tarsi with densely short spines．(figs．2，3，5，7)．Male(alate)：Length 2.1mm．Body brownish black to black with apex of mandibles reddish brown; antennae brown with most scapes blackish brown．The coloration of legs and wings similar to the alate female．Clypeus weakly emarginate，with a strong V-shaped median arina．Mandibles with 4 teeth．Middle tibiae with sparsely short spines peripherally.(figs·4，6). Host:Longhorned beetles，I.e. Semanotus bifaciatus sinoauster and Saperda populnea etc． Distribution:Guangdong Prov．(Guangzhou C.，Shantou C.)，Jiangsu Prov．(Xuzhou Pr.),Henan Proy.，Shaanxi Prov．(Yulin Pr．)，Shanxi ProV.(Taiyuan C．)，Hebei Prov．(Wangdu Co．)，Shandong Prov. Holotype:♀，Guangzhou City of Guangdong Prov.，1982.Ⅶ.10.Zhang Lianqin leg．Allotype：♂，same data as for holotype.Remarks：The apterous female of the new species resembles S.ephippium Saund．In most particulars， but differs from the latter in abdomen brownish black and antennal segment 1 long，about equal to segments 2-7 altogether．The alate female is somewhat similar to S.vigilans West.,but differs in pronoturn brownish black;the length of mesonotum about half as 10ng as the length of pronotum;and metanotum with two large yellowish brown markings．The alate male is allied to S．Nipponica(Yuasa)，but differs in first 5 antennal segments in the ratio of about 3:2:1.3:1.1:1；clypeus and mandibles except for extremes blackish brown; and antennae brown with most of scapes blackish brown．The species is named after Mr．Guan Ning for his kind help and interest in our Work．