343 

 Tropidia quadrata Say 



Xylota quadrata Say, Am. Entom., Vol. 1, PI. VIII; Oonipl. Works, Vol. 1, p. 14. 



Pnpariuni (PI. LXXXIII, Fi^. 17). — Length, 9 mm. Testaceous 

 yellow. Entire body opaque, covered with very short closely placed 

 pale hairs. Lower part of the lidlike anterior portion with 8 small 

 blackish thorns, 4 in a semicircle close to the lower extremity, 2 

 slightly higher placed, about midway between median line and lateral 

 suture, and 2 close to suture, about midway between lower extremity 

 and the median cross-suture; 2 strong thorns on each ventro-lateral 

 margin close to anterior margin of pupa; anterior respiratory organ 

 (Fig. 18) covered with small glossy knoblike swellings. Posterior ex- 

 tremity with 3 thorns close to ventro-lateral margin; posterior respira- 

 tory organ as shown in Figure 19, Plate LXXXIIL 



The pupal exuvium from which the above description was drawn, 

 is that of a male which bears the number 13549. The puparium was 

 found floating in the water at Flag Lake, near Havana, 111., August 3, 

 1895. Several were found on August 3 and 5, but only one imago 

 emerged (August 14). Two specimens, evidently newly pupated, 

 were found by Mr. Hart in a Sagittaria belt which had but recently 

 become inundated. 



Imagines in the collection here are from the following localities : 

 Algoncpiin, Chicago, Champaign, and Urbana, the dates ranging from 

 May 25 to July 17. There are also 2 specimens in the collection from 

 Westville, N. J., taken August 16. 



The early stages of the members of this genus have not previously 

 been described, and the larval habits are unrecorded. 



Brachypalpus frontosus Loew 



Braehj/palpus frontosus Loew, Berl. Ent. Zeitschr., 1872, p. 83. 



Larz-a (PI. LXXXIII, Fig. 12).— Length, 17 mm. White, with 

 the prothoracic thorns and setulje dark brown, anal respiratory organ 

 pale brown. Surface of entire body with closely placed, stout, small, 

 pale hairs. Front view of head and prothorax as in Figure 14; antennre 

 of moderate size, apices with two circular sensory organs; anterior 

 margin of prothorax with 3-4 transverse rows of blackish thornlike 

 processes which are recurved apically, the upper or posterior one 

 strongest ; prothorax with a strong outwardly directed, backwardly 

 curved thorn on each side and a small respiratory organ slightly nearer 

 to median line ; each segment with 10 slight cariuc-c, 4 on dorsum, one 

 on each dorso-lateral angle, one on middle of each lateral surface, and 

 one on each ventro-lateral angle, each carina with a group of hairs at 



