238 Illinois State Laboratory of Watmral JSittoiy. 



than basal diameter, beaiiug a very small eubcircular 

 rima; fringes formed of unequal pale spines, the longer 

 ones sparse on seventh segment above; outer terminal 

 teeth twice as large as lower pair, directed laterally and 

 slightly backwards; upper pair smallest, directed up- 

 wards; ventral fringe of last segment not noticeably 

 webbed ; lateral tufts rather high, not near ends of 

 ventral fringe. 



My material of this species is not in the best condition 

 for accurate comparisons. 



T. fulvulus Wied. 



One example from the banks of the Mississippi, in 

 Carroll county (northern Illinois), July 30. 



T. sagax 0,-S. 

 Illinois {Osten-Saclc&n*). 



T. nigrescens Pal. Beauv. 



An undersized larva supposed to belong with those oi 

 the next species pupated May 18, and on June 1 pro- 

 duced an imago of T. nigrescens, which is a closely re- 

 lated species. Most of the larvae treated above as stygiui 

 were very uniform in size and characters, and although 

 I cannot now separate these species in the larval stage, 

 I believe the bulk of my material, at least, was stygius. 

 We had previously taken the imago of nigrescens near 

 the Mississippi, in Jackson county, in southern Illinois, 

 August 10. 



P?//>(2, d .—Length 25 mm., diameter 5.5 mm. Palpal 

 eheaths narrowly separated, about one fourth as far 

 apart as the setae borne by the large frontal tubercles, 

 a smooth depressed space between them, without tuber- 

 cles. Lobes of carinate transverse ridges of head more 

 rounded and separated by a deeper notch than usual. 

 Abdomen a little more shining and more smoothly 

 wrinkled. Otherwise not different from the pupa of 

 iftygius (female) next described. 



• "Prodrome." 



