388 



dorsal segment consisting of about 12 strong, upwardly directed, 

 slightly backwardly turned thorns ; second segment with 6 shorter, 

 stronger thorns, between each pair of which are 3-4 very short, stout 

 thorns, and laterad of the outermost of the long thorns are 4-5 short 

 thorns and 6-7 long, slender spines in a transverse series which ex- 

 tends to postspiracular series ; segments 3-7 as second except that the 

 short thorns decrease in number progressively towards seventh and 

 are almost indistinguishable on the latter; eighth segment with 2 long, 

 widely separated thorns and laterad of these 2 short thorns and 1-2 

 spines; postspiracular area of first segment with 8-10 spines; each 

 ventral segment with a transverse series of closely placed bristles on 

 middle ; sixth and seventh segments each with a strong pair of bristles 

 slightly caudad of the regular transverse series, the pair on seventh 

 segment very noticeably stronger than the other bristles; apical seg- 

 ment with the upper thorns broad, short, flat, and somewhat leaf-like, 

 median thorns small (PI. LY, Fig. 8). 



The foregoing description is drawn from the pupal exuvium of a 

 male obtained by C. G. Ainslee at Orlando, Fla., and kindly submitted 

 for examination by J. J. Davis, of the U. S. Bureau of Entomology 

 (Webster No. 10861 A). 



The species is represented in our collection by imagines from Car- 

 bondale, Thebes, Metropolis, and Pulaski, all in the southern portion 

 of Illinois ; and by one specimen from Virginia. 



The larva is predaceous upon white-grubs. 



Erax aestuans Linne 



Asilus aestuans Wiedemann, Dipt. Exot., Vol. 1, p. 200. (1821) 



Pupa. — Length, 18 mm. Yellowish testaceous, slightly shining; 

 armature dark brown, glossy; apices of wings slightly browned. 



Upper pair of cephalic processes sharp at apices, not noticeably 

 flattened above ; seen from above, slightly divergent apically, the dis- 

 tance between their apices distinctly greater than length of either 

 thorn; lateral process with thorns sharper than in luaculatus (PI. LY. 

 Fig. 6) ; apices of mouth-parts carinate. Thoracic spiracle much 

 smaller than in macitlatus, and more elevated, the reniform area 

 slightly concave ; pair of thorns at base of middle leg slender, sharp, 

 the anterior one less than two thirds the length of the posterior (Fig. 

 7) ; protuberance above base of wing similar to that of maculatus; 

 protuberance on middle of disc of wing very small; apices of wings 

 extending midway between apices of fore and mid tarsi. Abdominal 



