ORT ALID^J — ID AN A. 115 



hyaline dots, contained within the black border of the costa, are 

 much less clear in the present species, especially the first and the 

 third among them. 



Hab. California (Agassiz). 



Gen. IV. ID ANA nov. gen. 



Charact. — Body robust. Hairs very short everywhere ; thorax with 

 bristles on its posterior and lateral borders only. 



AntenncB of medium size ; third joint oval, but little longer than 

 the rather large second joint. Face obtusely carinate between the 

 very long antennal foveae. 



Palpi of moderate size ; the mentum moderately turgid. 



Wings narrow and very long ; first longitudinal vein towards its end 

 provided with bristles to a considerable extent ; third and fourth 

 longitudinal veins converging towards their end; anal cell not 

 drawn out in the shape of a lobe. 



This genus contains conspicuous pollinose species ; their thorax 

 is marked with distinct black stripes and the abdomen banded 

 with black, the design of the wings not unlike the genus Ptero- 

 poscila, while the general shape of the body reminds of the true 

 species of Ortalis. 



1. I. marginata Say. 9 .—(Tab. VIII, f. 16.) Alse colore fusco- 

 nigro et luteo pulchre variegatse, ima cellulse marginalis basi, triente 

 apicali cellulse basalis primse, cellulisque posterioribus duabus primis 

 prseter venarum limbos pure hyalinis, angulo postico et cellula poste- 

 riore tertia fere tota cinereo-hyalinis. 



The wings with a handsome brownish-black and brownish-yellow picture; 

 the extreme basis of the marginal cell, the last third of the first basal 

 cell, as well as the first two posterior cells, pure hyaline, with the excep- 

 tion of the borders of the veins, inclosing them ; the posterior angle 

 and the greater part of the third posterior cell grayish hyaline. Long, 

 corp. 0.34; cum terebra 0.45 ; long. al. 0.46 lin. 



Syn. Ortalis marginata Say, Journ. Acad. Phila. VI, p. 183, 2. 



Head reddish-yellow. Front orange-yellow, opaque, with the 

 exception of the immediate proximity of the ocelli and of the two 

 little callosities, descending from the vertex and bearing the 

 frontal bristles ; the sides more orange-red, usually infuscated 

 above the antennae ; on each side a rather narrow border of yel- 

 lowish pollen. Antennae of medium length ; the first two joints 

 of the coloring of the head ; the second rather large ; the third 

 almost orange-yellow, of an oval shape, and but little longer than 



