DESCRIPTION OF PLATE VII. 
These Positive Photographs from Collodion Negatives, taken by 
J. Delves, Esq., illustrate that gentleman's, Mr. Shadbolt's, and Mr. 
S. Highley's papers on Photography. 
Fig. 
1. Spiracle and Trachese of the Silkworm, magnified 60 diameters, exhi- 
biting the elastic spiral fibre between the layers of the air vessels. 
2. Proboscis of the Fly, magnified 180 diameters, showing the divided 
absorbent tubes. 
