252 THE CANADIAN ENTOMOLOGIST. 



Length at rest 13-16 inch, in motion 15-16 inch. Head yellow 

 brown, with a purplish brown line running down each side, being appar- 

 ently the prolongation of the band of same colour below the subdorsal 

 whitish stripCj and on it are the ocelli, but in some individuals this line is 

 obscure. Cervical shield large, practically covering the whole of the first 

 thoracic segment, yellowish, lighter than the head, edged on each side 

 with purplish brown, the continuation of that shade below the subdorsal 

 whitish line. 



Colours of body practically the same as in ruiila, being purplish 

 brown, with dorsal and subdorsal pale cream colour or whitish stripes, 

 which are not broken in any part, but are continuous from head to tail. 

 The purplish brown of the first four abdominal segments has the appear- 

 ance of being deeper in colour than on the rear segments, but this is 

 pardy owing to the whitish stripes being narrower on these segments 

 than on those behind them. Warts strongly marked, darker than the 

 purplish-brown ground colour, IV on the seventh abdominal segment 

 being slightly above the level of the spiracle, setae simple. Anal shield 

 large, yellowish like the cervical shield. 



On receipt of the specimen of cerata which I sent to the British 

 Museum, Sir George Hampson wrote me that he considered it an un- 

 marked form oi limpida, Gn., but it appears to me that this must be at 

 least doubtful until more is known of limpida, the types of which came 

 from Illinois, especially as that species is not known to have an un- 

 marked form, and in view of the extreme closeness of some of the species, 

 as shown by some of Mr. Bird's more recent discoveries. 



Mr. Bird next dealt with the forms which I described as thalictri 

 and \'2ir. perobsoleta, pronouncing the latter identical with frigida, Smith, 

 on the ground that there was " nothing in the description and nothing in 

 the types, except the usual difference between flown and bred material " 

 to separate the forms. I may be permitted to point out that it was on 

 precisely identical grounds that my cerata was pronounced a synonym 

 oi nelita, Strecker, as we now know, through Mr. Bird's discovery, errone- 

 ously. Mr. Bird points out that in Dr. Smith's plates representing genital 

 armature* Fig. 25 was supposed to be that of cerussata, while Fig. 26 

 represented yr/^/V/*^!, Sm., and says that afterwards No. 25 was found not 



*Trans. Amer. Ent. Soc, XXVI., pi. I., II. 



