ART. 15. REVISION OF ICHNEUMON-FLIES MUESEBECK. 21 



Apparently most of the species of Mici-ogaster are solitary para- 

 sites, always of lepidopteroiis larvae. The cocoons are of white silk 

 and are never surrounded by a mass of fluffy loose silk, as is often 

 true in the genus Apanteles. Although a considerable amount of 

 material is found in most collections, few of our known species are 

 particularly common, Microgaster gelechiae Riley being perhaps the 

 best known of these. 



KHT TO THE NORTH .AMERICAN SPECIES OF MICROGASTER. 



1. Propodaim without a distinct median longitudinal carina, very weakly 



roughened and usually provided with a more or less distinct areola ; second 

 abdominal tergite much shorter than the third, transverse, defined laterally 

 by oblique grooves, and mostly smooth and shining; ovipositor sheaths 

 more than half as long as the abdomen ; second cubital cell minute, often 



indistinct -• 



Propodeum always with a prominent median carina and usually coarsely 

 rugose 3. 



2. Posterior coxae, femora and tibiae wholly testaceous; second and third 



abdominal tergites testaceous 1- zonaria Say. 



Posterior coxae deep black on basal half ; posterior tibiae with the apical 

 third blackish ; second abdominal tergite black. 



2. ecdytolophae, new species. 



3. First dorsal abdominal plate long and narrow, at least three times as long as 



broad at apex, never broader at apex than at base; the second abdominal 



tergite mostly smooth and polished 4. 



First dorsal abdominal plate never so long and slender; second abdominal 

 tergite usually rugose 9. 



4. Second dorsal abdominal plate deeply and angularly emarginate anteriorly 



to receive the plate of the first tergite, and without longitudinal impressed 

 lines medially ; the first plate narrowest in the middle, the sides curving 



inward. Length 4 mm. or more 5. 



Second dorsal abdominal plate not emarginate anteriorly, and provided with 

 two longitudinal impressed lines medially ; first dorsal ab<lominal plate 

 narrowest at apex. Length not over 2.5 mm 7. 



5. Wings hyaline ; all coxae and femora black ; abdomen mostly black. 



3. garmani (Ashmead). 



Wings maculated; all coxae and femora reddish-testaceous; abdomen mostly 



red 6. 



6. Head and thorax, except propodeum, testaceous 4. mediata Cresson. 



Head and thorax entirely black 5. calliptera Say. 



7. All coxae entirely pale yellow; mesoscutum and scutellum with distinct 



separate punctures 6. iridescens Gre.sson. 



Posterior coxae black ; mesoscutum and scutellum coarsely confluently punc- 

 tate 8. 



8. Posterior femora black ; second cubital cell exceedingly minute, indistinct : 



median area on second abdominal tergite minutely shagreened. 



7. xanthaspis (Ashmead). 

 Posterior femora blackish only on apical third or half; second cubital cell 

 normal, the second intercubitus distinct; median area on second abdom- 

 inal tergite polished 8. bakeri, new species. 



