192 ME. W. H. ASHMEAD ON THE PABASITIO HYMENOPTEEA 



DissoMPHAiiUS, Ashmead. 



This genus is allied to Isobrachium, Forster, and is described 

 in my * Monograph of the North-American Proctotrypidae.' As 

 the work has not yet appeared, I give here the essential characters 

 for the recognition of the genus : — 



Maxillary palpi 4-jointed ; labial palpi 3-jointed. Mandibles 

 3-dentate. Antennge 13-jointed, filiform, submoniliform, the first 

 flagellar joint always smaller than the second, the joints beyond 

 submoniliform. Mesonotum with or without furrows. "Wings 

 with two basal cells of an equal length ; the transverse medial 

 nervure straight ; parastigma not developed ; the stigma oblong- 

 quadrate, the radial vein very long. Legs slender, the femora 

 not much swollen. Abdomen oblong-oval or oval, depressed, 

 subpetiolate ; the second segment is always much longer than 

 the third, and bears two warty-like tubercles or nipples, which 

 are variously situated, often placed in a fovea or surrounded by 

 a grooved line. 



The two warty-like tubercles or nipples, on the second abdo- 

 minal segment, are a unique character, and with the other 

 characters mentioned will readily distinguish it from all other 

 genera in the Bethylince. 



The four species from St. Yincent may be thus tabulated : — 



Mesonotal furrows wanting or with only traces 



anteriorly 2. 



Mesonotal furrows complete, distinct. 

 Metathorax rugose, with a medial carina. 

 Transverse medial nervure straight. 

 Legs reddish yellow. 



Second abdominal segment with two 



hairy tubercles in fovese towards tJie 



base, widely separated ; flagellum 



fuscous towards the tip, the pedicel 



oval, larger than the first flagellar 



joint, the second and the joints 



beyond longer than the first, about 



one and a half times as long as thick. D. tuber culatus, sp. 



Metathorax almost smooth above, the sides 



and face of the truncature finely sculptured. 



Legs honey-yellow. 



Second abdominal segment with two 

 tubercles close together ; flagellum 

 fuscous, the pedicel larger than the 



