482 ANNUAL REPORT OF NEW-YORK 



SUPPLEMEXT. 



of short pale yellow hairs evenly shorn at their tips and projecting out from 

 the surfoce, and opposite these tufts on the inner surface is a small round spot 

 of the same yellow color, formed of exceedingly fine lines radiating from the 

 centre to the outer margin of the spot, which is bounded by an elevated ring 

 or hoop which is also of a pale yellow color. From this description the ento- 

 mologist will perceive that the pupa-case of this fly is analogous in almost 

 every particular with those of many other insects of this order. 



The FLY is a female and measures 0.70 in length to the tip of its abdomen 

 and wings. Its head is black above, with close fine punctures, and is densely 

 covered with short erect black hairs; its under side is brownish flesh-colored, 

 closely punctured and clothed with white hairs which incline inward towards 

 the mouth. Upon each cheek, below the eye and adjacent to the outer edge 

 of its orbit, is a large shining black dot, in which the punctures are coarser 

 and more distant from each other, and the space between this and the eye is 

 darker brown. The antennae are dark liver-brown and have a few whitish 

 hairs overlying their bases, like eye-lashes. Their bristle is black at its base 

 and the fine hairs with which it is ciliated are whitish. The cavity in which 

 the antennae repose has an ash-gray reflection, and on each side between this 

 cavity and the eye is an elevated smooth shining space which is coarsely 

 punctured. The thorax is black, finely punctured and clothed with soft hairs 

 which incline backwards and appear of a tawny brown color when viewed 

 from above but when seen from the side are white slightly tinged with yellow. 

 Upon each side these hairs are much more dense, and half way from the wing- 

 socket to the lower edge of the eye is a dot formed of black hairs. The scutel 

 is black and clothed with black hairs. Beneath it on each side is a small yel- 

 lowish-white dot, from which a short white line extends outwards. The 

 abdomen is black, shining, densely punctured and covered with fine short hairs 

 which incline backwards, those at the base being longer and those on the last 

 segment tawny yellowish-white when viewed laterally but appearing black 

 "when seen from above. The segments are prolonged to the under side of the 

 body, where their ends are of a glaucous grayish color with a large black dot 

 upon each. The legs are black and covered with short black hairs, those 

 towards the tip of the forward thighs on the hind side being yellowish white. 

 The imngs are smoky brown and imperfectly hyaline. At the base on their 

 inner side is a large lobe of a square form with its corners rounded and its in- 

 ner edge slightly concave. The winglets are blackish and opake with a nar 

 row chestnut-brown margin. 



A specimen of this same insect, sent me from west of Arkansas by AVilliam 

 S. Robertson, varies in having the hairs upon the last segment of the abdomen 

 much more dense, causing this segment to appear of a yellowish-white color, 

 and the ends of the other segments are but obscurely tinged with gray without 

 any black dot. 



From what has now been stated I think that every one will 

 agree with me in the opinion that it is by this fly that the squir- 

 rels in our country are emasculatedj and that this remarkable 



