RILEY NOTES ON NORTH AMERICAN MICROGASTERS. 297^ 



the group. It is with a view of assisting in this work that I have 

 been led to prepare these notes and to describe the few species 

 which more particularly interest me. My thanks are due ta 

 Messrs. McCalla & Stavely for the loan of figures 6 and 7, and to 

 Mr. W, H. Patton for assistance. 



CHARACTERISTICS OF THE GROUP. 



The Microgasters are distin- 

 guished from the other members 

 of the family Ichneumonidae by 

 ^"^^^^=^^===^^_i jy their hairy eyes and iS-jointed 

 "'* antennae. The second cubital 



Fisr. 2. — Front ■win? of Microp-aster g:elechiEe> i i. r ^i • • ^i 



^enlarged; /;««r first median area; sma, arcolct of the WingS in the ma- 

 second t\£"^^:\^^^{^^^k jority Of the species is not closed 

 do.; r<7, radial area. externally (Fig. i), but whcn 



complete (Fig. 2, sea) this areolet is quite small. The radial area 

 (Fig. 2, ra) of the wings is never complete, and that portion of 

 the radial vein extending from the stigma to the second cubital 

 areolet is the only portion of the vein that is distinctly marked,- 

 this portion together with the basal vein of the second cubital 

 areolet forming what has been described by some authors as the 

 " outer side " of the first cubital areolet. The ovipositor is gene- 

 rally short, not extending beyond the tip of the abdomen ; but in 

 a number of species it is exserted, as in Microgaster gelec/itce, 

 where it is one-half the length of the abdomen ; and sometimes it is 

 equal to the whole abdomen in length, as in Apanteles mega- 

 thymi. The body is generally black, the legs pale, and the wings 

 transparent with a dark stigma ; the abdomen is sometimes 

 marked or banded with red, the antennie vary from black to red, 

 and the palpi are whitish or reddish. The thorax is more or less 

 densely punctate and the basal joints of the abdomen afford good 

 characters in the presence or absence of sculpture. The size va- 

 ries greatly in different species, but none equal one-fourth of an 

 inch in length and the majority do not exceed one-eighth. 



Foerster, in his " Synopsis der Familien und Gattungen der 

 Braconen," published in 1862, separated two genera from the old 

 genus Microgaster, and H. Reinhard, in the "Deutsche Entomo- 

 logische Zeitschrift" for iSSo, p. 353, shows that these genera are 

 well, founded. They may be distinguished by the following 

 characters : 



