40 MISC. PUBLICATION 17 4, U.S. DEPT. OF AGEICULTURE 



pedicel about twice as long as thick ; one strongly transverse ring joint ; f unicle 

 5-jointed, tlie joints sucessively increasing slightly in thickness, the first joint 

 a little less than twice as long as thick, shorter than pedicel; second to fifth 

 joints each very slightly longer than broad ; club compact, 3-jointed, the joints 

 not distinctly separated, the separation between joints 2 and 3 being especially 

 vague. Thorax finely rugulosely sculptured, the sculpture on prescutum and to 

 some extent on pronotum and scutellum taking the form of sparse irregularly 

 transverse rugae; pronotum large, subquadrate, about twice as broad as long; 

 mesoscutum shorter than pronotum, parapsidal grooves complete; scutellum 

 equal to prescutum ; axillae separated ; propodeum with a narrow, shallow, 

 foveolated, median depression, the surface of propodeum outside of the groove 

 finely rugulose ; pleura with fine, punctate sculpture. Legs with all the femora 

 slightly thickened ; basal joint of hind tarsi scarcely longer than apical joint ; 

 hind tibia with a row of stiff spines or bristles along its posterior margin. 

 Wings normal, extending well beyond apex of abdomen, a little less than two and 

 one half times as long as broad, bare behind the submarginal vein except for 

 a few (from 4 to 8) erect stiff hairs marking the obsolete median and basal 

 veins ; costal cell with fine cilia on its ventral surface, bare above ; marginal cilia 

 short; marginal vein very short and thick, less than one fourth as long as 

 submarginal, wider distally than at base ; postmarginal vein very short, sub- 

 obsolete ; stigmal vein approximately half as long as marginal. Abdomen about 

 as long as thorax, ovate, distinctly compressed from the sides, and strongly 

 petiolate ; petiole nearly as long as hind coxae, slender, rugulose ; body of 

 abdomen smooth or nearly so, the fourth tergite (not counting the petiole) 

 slightly the longest, fifth tergite short, the following tergites concealed ; ovi- 

 positor not exserted. Color reddish yellow ; a spot on occiput and an adjacent 

 area on neck of pronotum, a spot at each anterior lateral angle of mesoscutum 

 (these spots sometimes united to form a transverse band across the anterior 

 margin of mesoscutum), sutures at lower margin of axillae, transverse band at 

 base of propodeum connecting with a median longitudinal stripe, prosternum, 

 mesosternum, metasternum, abdominal petiole, and usually a large triangular 

 spot on each of the first three abdominal tergites, black ; antenna and legs con- 

 colorous with the body, the hind tibia sometimes stained with fuscous on its 

 outer side ; wings hyaline with a narrow transverse band of fuscous embracing 

 the marginal vein and extending about two thirds of the distance across the 

 wing. 



Male. — Length 2 mm. Similar to the female except that the funicle is 

 4-jointed ; the first funicle joint as long as the pedicel and a little more than 

 twice as long as thick, second funicle joint about twice as long as broad, third 

 and fourth each a little longer than broad, club composed of three subequal 

 and closely united joints; abdominal petiole a little longer than hind coxae, 

 the abdominal tergites beyond the third (not counting petiole) retracted. Color 

 as in the female except that the scutellum usually has a large black spot 

 apically. 



Kedescribed from the type specimens. 



REVIEW OF LITERATURE 



Decatoma amsterdamensis was originally described, together with 

 a number of other species of Chalcidoidea, in a small pamphlet pri- 

 vately published and distributed by A. A. Girault in 1917, the types 

 having been reared in 1914 and 19±5 by W. J. Phillips at Penn Yan 

 and Auburn, N.Y. The species was included by Leonard in his list 

 of the insects of New York in 1928, and Balduf included a redescrip- 

 tion of it in his revision of the tribe Decatomini published in 1932. 



HOSTS AND LIFE HISTORY 



This species is probably normally parasitic upon the species of 

 joint worms. In the original description Girault stated that the types 

 were reared in connection with Hwrtnolita (=Isoso??ia) at Penn Yan, 

 N.Y., by W. J. Phillips. Balduf gave the additional information 

 that three specimens in the National Museum collection were para- 



