HYDRELLINA. 157 



whitish pollen, its middle portion flavescent below. Facial orbjtas 

 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. 

 Hab. 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 antenna?, a larger portion of the abdomen 

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

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

 opposita, evidently prove it to be a distinct species. 



Note. Some specimens have ./ire 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. debs I is LOEW. . (Translated from Berl. Entom. Zeitschr. 1861, 

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

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

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

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

 hyalinis, circa venas transversales 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. 

 Long. al. 0.064- 



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

 white marginal line on each side and the rather large ocellar 



