HYDRELLINA. 157 



whitish pollen, its middle portion flavescent below. Facial orbits 

 of the eyes narrow, with a white reflection. Thorax obscure, 

 cinereous brown above, with very narrow, obsolete darker lines. 

 Pleurae dark cinereous. Scutellum concolorous with the thorax. 

 Abdomen black, very glossy, a large obscurely cinereous opaque 

 basal spot, not attaining the posterior margin of the second seg- 

 ment. Legs yellowish ferruginous, last joint of tarsi black, base 

 of femora sometimes fuscous. Wings cinereous hyaline, veins 

 black; short stumps of veins clouded with black, proceed from the 

 second, third, and fourth longitudinal veins ; the third vein emits 

 four such stumps, all of which, except the last, are opposed to 

 similar stumps on the second vein ; the last segment of the fourth 

 vein generally emits two stumps ; the ordinary transverse veins are 

 broadly clouded with black. The second segment of the costa is 

 almost twice as long as the third. 



Sab. Pennsylvania. Washington. (Osten-Sacken.) 

 Observation. — Phil, opposita is very like P. punctato-nervosa 

 Fall., but distinguished by a more brown color, a more narrowed 

 face, darker legs and antennae, a larger portion of the abdomen 

 colored with black and by a smaller number of dots on the wings. 

 The facial orbitee of the eyes, which are much narrowed in P. 

 opposita, evidently prove it to be a distinct species. 



Note. — Some specimens have Jive stumps on the third vein, opposed to 

 four on the second, and more than two stumps on the last segment of the 

 fourth vein. 0. S. 



3. P. del>ilis Loew. % . (Translated from Berl. Entom. Zeitschr. 1861, 

 p. 356, by R. Osten-Sacken.) — Nigro-cinerea, opaca, antennis totis nigris, 

 fronte atra opaca, triangulo ocellari maximo, nigro-cinereo, ultimo abdo- 

 minis segmento atro, nitido, pedibus obscuris, genibus, tibiarum anteri- 

 orum apice, tarsisque fiavescentibus, horum apice nigro, alis cinereo- 

 hyalinis, circa venas trans versales infuscatas limpidioribus. 



Blackish-cinereous, opaque, antennae entirely black, front black, opaque, 

 ocellar triangle very large, blackish-cinereous, last segment of the ab- 

 domen black, shining, feet obscure, knees, tip of the anterior tibiae and 

 tarsi yellowish, tip of the latter black, wings cinereous-hyaline, with 

 clearer spaces round the infuscated transverse veins. Long. corp. 0.05. 

 Lorjg. al. 0.064. 



Blackish-cinereous, opaque. Front black, with a very narrow 

 white marginal line on each side and the rather large ocellar 



