538 



THE ENTOMOLOGIST. 



Inostemma areolata, female ; antenna of female ; antenna of male ; antenna 

 of I. scrutator; abdomen of male I. areolata, vertical section. 



The wing-striicture of the Platygaster tribe is quite different 

 from that of the Mymaiida3 : in the latter the vein or bone 

 takes the initiative, and tlie membrane is wholly wanting or 

 is only slightly developed ; in the former the vein is generally 

 not existent, or is merely rudimentary. Platygaster appears 

 in most parts of the world, and is dependent on Cecidomyzidae 

 for its means of subsistence between the egg-state and the 

 perfect-state : it is much more abundant in North Europe 

 than in South Europe, and may, like many other minute 

 Hymenoptera and Diptera, have been partly expelled from 

 the latter region by the multitude of minute ants which occur 

 in the vegetation. Piof. Foerster's synopsis of the genera is 

 translated as follows : — 



A. Submarginal vein with a knob at the tip. 



a. Tarsi 4-jointecl. .... Iphitrachelus. 



b. Tarsi 5-jointed. 



=;= Antennae 9-joiuted, serrated in the male. - Allotropa. 



*=;= Antennae lO-jointed, not serrated in the 



male. 

 f Wings with a basal and middle vein. 

 I Three last joints of the flagellum much 



larger than the preceding joints, forming 



a club. ..... Metaclisis. 



