CHARLES W. HOOKER. 43 



Length, 10-20 ram. ; wing, 9-18 mm. ; spread, 20-38 mm. ; antennae, 

 14-22 mm. 



Fulvo-ferruginous, varying from flavous to ferruginous, the light 

 specimens usually with dark ferruginous markings. 



Head with dorsal and posterior aspects yellowish, frequently with 

 irregular narrow bands of yellow surrounding the eyes and writing 

 behind the ocelli ; antennae as long or longer than the body ; ocelli 

 large, well separated, the posterior a little distant from the tops of the 

 eyes; eyes large, emarginate ; clypeal fovese distinct ; mandibles bident- 

 ate, tipped with black. 



Thorax slightly lighter colored than the rest of the body ; mesonotum 

 with three longitudinal ferruginous stripes more or less distinct ; meta- 

 thorax with inconstant carinae, or smooth and finely punctured ; two 

 transverse and six longitudinal carinae are frequently evident, but are 

 often more or less indistinct and sometimes entirely wanting. 



Wings hyaline, often slightly tinged with fuscous ; iridescent, stigma 

 and most of the costa fiavous,* nervures otherwise black ; discocubital 

 vein angularly broken and appendiculate, the appendix varying con- 

 siderably in length ; nervulus antef ureal to interstitial, nervellus broken 

 at or near the middle, a small glabrous spot in the discocubital cell 

 near the stigma ; legs of the general color, claws pectinate ; abdomen 

 generally strongly compressed, often darker at the apex, varying some- 

 what in shape, slender or quite broad. 



In describing this species I have examined over 500 speci- 

 mens from all parts of North America, the West Indies, and 

 some from South America. 



Type. — Lost. 



This species shows a wide variation in color, and light and 

 dark specimens are common ; Say's type must have been 

 one of the light forms, many of which are more or less dis- 

 tinctly marked with longitudinal ferruginous stripes on the 

 mesonotum. Sometimes the stripes are lacking even in the 

 lighter forms, while in the dark forms the whole thorax is 

 ferruginous, and the mesonotal stripes are consequently 

 obliterated. Between these two light and dark forms are all 

 sorts of gradations. The wings are normally hyaline but 

 are often tinged with fuscous ; the length of the appendix of 

 the discocubital vein varies from almost rudimentary to long ; 

 the areolation of the metathorax varies considerably, it being 

 sometimes smooth, without carinas, and sometimes strongly 

 * The stigma is sometimes marked with ferruginous or black. 



TRANS. AM. HNT. SOC, XXXVIII. 



