1878. ] The Smallest Insect Known. 445 
prove to be another important factor in solving questions concern- 
ing the food supply of ants under both ordinary and extraordi- 
nary circumstances. Mr. Edwards is now pushing his observations 
upon the Spring larve of this butterfly, assisted by the micro- 
scopic skill of Prof. J. Gibbons Hunt, M. D., of Philadelphia. 
O: 
THE SMALLEST INSECT KNOWN (PTERATOMUS 
PUTNAMII). 
BY HON. J. D. COX. 
{hag minute size of this species, which is said to be the smallest 
insect known, is probably the reason why it has been so little 
observed, and will justify a somewhat detailed description of a 
Specimen which was caught and mounted in balsam last July. 
was examining the scissor-like mandibles of a leaf-cutter bee 
(Megachile centuncularis), when I noticed upon the surface of the 
water in which the larger insect was dissected, a mere mite which 
_ Seemed to have life. Upon transferring it to a smaller cell of water 
and putting it under the microscope, it proved to be one of the 
most beautiful little creatures of the insect world, and a rarity 
which made it no ordinary prize. 
Whilst it was not difficult to identify it as the Preratomus Put- 
nami from Prof. Packard’s description in the “Guide to the 
Study of Insects,” it was also evident that the specimen which the 
Professor had before him in making his drawing and description, 
had been injured, and shorn of some of its parts, and that some- 
thing might be added to our knowledge by putting the “ winged 
_. atom” in shape for permanent preservation. 
The first suggestion as to method was acted upon at a venture, 
and it turned out a rather lucky hit. A clean slide and cover, 
and the soft balsam were at hand. Her littleness was taken 
` carefully on the point of a needle, dried against a bit of blotting 
Paper, immersed in a drop of balsam and the cover put on, leavipg 
the arrangement and display of the parts almost wholly to the 
effects of capillary attraction. 
The cut is from an accurate tracing by means of the camera, 
- and except as to the position of the wings, will give at once a 
Correct idea of the little creature. The wings were forced some- 
what out of place in the mounting, but with the aid of: the binoc- 
