THK CANADIAN ENTOMOLOGIST." .V> 



number of individuals are examined, each species is found to vary so 

 much in itself, as to render these unreliable as distinguishing traits. 



The accompanying diagrams (Fig. 24), which 



are sketched from memory, arc. perhaps, a little 



inaccurate and exaggerated ; but will serve to 



illustrate the true distinguishing traits at a glance 



a' #.' q% • ^z — a > a 2 showing the larval horn and pupal hump 



of Disippus, and b' fa the same of Ursula. \w 

 the full-grown larva of Disippus, the horns on joint 2 are, on an 

 average, but 0.20 inch long ; while in Ursula they average 0.40. or 

 double the size : in Disippus they are heavy, decidedly club-shaped, 

 and generally covered with granulations or prickles to the base ; while 

 in Ursula they have a more uniform diameter, are more slender, with 

 fewer prickles at the end, and with the basal half generally quite smooth 

 and highly polished. In the pupa of Disippus the hump is less regular, 

 with the upper edge less rounded than the lower, so that an imaginary 

 line run through it as at a 1 leaves the larger portion below. In the 

 pupa of Ursula, on the contrary, the hump is quite regular, the upper 

 edge being, in outline, almost the counterpart of the lower, so that 

 the same imaginary line would leave the larger portion above. 



I have not my library at hand, and cannot tell whether Boisduval, 

 Smith and Abbott, or any other authors have pointed out these dis- 

 tinguishing characters ; but I have an impression that they have not, 

 and more modern authors certainly have not. 



London, Eng., July 13th, 1871. 



[Mr. Riley's friends will no doubt be glad to learn, from the date 

 of the foregoing article, that he has safely crossed the Atlantic, and 

 that, though amongst old friends and old haunts, he has not lost his 

 interest in the investigation of the insects of this continent. We wish 

 him much enjoyment in his visit to his native land, and a safe return to 

 his valued labours in the Western world. — Ed. C. E.] 



