ASHMEAD : CLASSIFICATION OF THE CHALCID FLIES 259 



Marginal vein hardly twice the length of the stigmal vein ; antennte 11-jointed ; abdomen not long, 



lanceolate Aximopsis Ashmead, gen. nov. (type A. morio Ashm.). 



3. Marginal vein four or more times longer than the stigmal ; antennae 11-jointed, the fuuicle joints long, 



binodose, each joint with two whorls of long hairs Axima Walker. 



Marginal vein hardly twice the length of the stigmal vein Aximopsis Ashmead. 



Tribe II. Isosomini. 



All the species falling in this tribe are phytophagous and thus differ in habits 

 from all of the other tribes. 



The group approaches very close to the Eurytomini and many of the species 

 were at first described under the genus Eurytoma. There is, however, a well 

 marked structural difference between them, and the tribe may be easily separated 

 by the characters made use of in my table of tribes. In having a long metathorax 

 and in the antennal characters of most of the genera, the Isosomini approach 

 nearest to the Aximini, but the horned head in the latter is sufficient to keep them 

 apart. 



TABLE OF GENERA. 



1 . Females 2 



Males 8 



2. Apterous 7 



Winged. 



Marginal vein always longer than the stigmal vein 3 



Marginal vein shorter than the stigmal vein, the latter very oblique, extending off from the 

 marginal at an angle of thirty degrees. 



Head and thorax umbilicately punctate, the frons with a deep antennal furrow ; abdo- 

 men elongate, conic-ovate, the dorsal segments subequal, as in Isosoma. 



Isosomodes Ashmead (type Isosoma gigantea Ashm.). 



3. Metathorax sloping or rounded behind, not abruptly and squarely truncate behind 4 



Metathorax quadrate, abruptly and squarely truncate behind. 



Mesonotum delicately umbilicately punctate ; abdomen ovate, slenderer than the thorax, the 

 second segment the longest, the others about of an equal length. 



Isosomorpha Ashmead (type I. europse Ashm.). 



4. Thorax more or less distinctly umbilicately punctate, punctate or shagreened, opaque, never smooth 



and shining ; antennse usually 11-jointed, with 1 ring-joint, the funicle 5-jointed 5 



Thorax smooth and shining, impunctate or at the most feebly microscopically shagi'eened 6 



5. Mesonotum umbilicately punctate, punctate or rugulose ; abdomen usually long, conically pointed, 



the segments subequal in length, the fouith not or only slightly longer than the third. 



Isosoma Walker (type Ichneumon verticellata Fabr.). 

 Mesonotum with the middle lobe nearly smooth, delicately punctate, with usually delicate transverse 

 aciculatious anteriorly ; abdomen very long, conically pointed, the fourth segment very long. 



Euoxysoma Ashmead (type Systole hrachyptera Ashm.). 



6. Pedicel longer than the first joint of the funicle, the joints of the latter moniliform or nearly ; abdomen 



ovate, with the fourth segment much longer than the others, except the second ; postmarginal vein 

 scarcely longer than the stigmal vein Isosomocharis Ashmead (type /. sulcat Ashm.). 



