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ripened last July, and were taken into the house in April, 

 1837, I found a puparium of the Hessian Fly ; began to cut it 

 open, and found witliin a Hessian Fly nearly matured. Opened 

 only the anterior part of the puparium ; but the animal soon 

 squirmed itself out, enveloped in a thin scarf. The puparium 

 was left entirely clean ; of course the thin skin, or exuvia, was 

 yet upon the animal. The antennae, legs, eyes and wings, as 

 seen through this covering, were black. The abdomen Avas 

 composed of eight annuli, besides a small appendage, mostly of 

 an internal red color ; each annulus sparingly clothed with dark 

 hairs. The animal worked its abdomen back and forth, and 

 in about twenty minutes the posterior part of the abdomen and 

 the ovipositor could be clearly seen within, detached from the 

 exuvia. The only split in this scarf-case was on the thorax." 



I am somewhat puzzled to understand how the Hessian Fly 

 can make its way through the stout leathery puparium. Those 

 near the foot of the stalk are battered and shattered by the 

 weather, and are easily pierced, but those higher up seem to 

 me too firm to be forced by so feeble an animal. In these 

 latter cases another difficulty much more serious lies in the 

 way, — the sheath of the leaf must be pierced ; this is often 

 quite hard and firm. This tlicoretical difficulty is perhaps 

 never a practical one, for the parasites take good care of all 

 such cases. 



HARRIS TO HERRICK. 



Cambridge, Mass., Sept. 15, 1847. 



Being very desirous of comparing Miss Morris's Cecidomyia 

 with recent specimens and the genuine Hessian Fly, I take the 

 liberty of reminding you of your promise to obtain for me if 

 possible some of both species for examination. 



There are discrepancies in the published descriptions of the 



