PRESERVATION OF CATERPILLARS BY INFLATION. 823 
not be more than half à millimetre iņ diameter ; the cut represents 
it magnified nineteen diameters (Fig. 77). 
The straw. Mr. Goossens of Paris, my courteous instructor in 
this art, who possesses a collection of nearly a thousand species 
of inflated caterpillars, uses nothing but ordinary wheat straw, 
choosing stout, dry pieces of various sizes, the cross section of 
which is perfectly circular; with these he inflates the smallest 
micros and the largest sphingide. Various modifications have 
been suggested ; a glass tube drawn to a fine point, and provided 
with a pair of spring clips to attach to the caterpillar, is a favorite 
form; the Germans use this largely, and sometimes attach the 
caterpillar by threads passed around the anal prolegs. Dr. Le- 
onte informs me that- Dr. Gemminger uses a finely pointed tube 
with an elastic bulb attached like a rubber syringe. Mr. Riley 
suggests (as his drawing represents) still another mode, which is 
to pierce a piece of soft wood along the grain with a fine heated 
wire and then sharpen toa point the tube thus formed, to bein- 
serted in the caterpillar; a tube is also inserted in. the other end 
(see Fig. 76). For myself I prefer the simple straw. 
The operation. Kill the subject by a drop of ether or by a 
Plunge in spirits; if it be a hairy caterpillar it should remain at 
least half an hour in alcohol and then rest on bibulous paper for 
forty-eight hours; otherwise the hairs drop off in the subsequent 
operation. Then placing the caterpillar in the left hand, so as to 
expose its hinder extremity beyond the gently closed thumb and 
first two fingers, enlarge the vent slightly at the lower edge by a 
vertical cut with the scissors; next lay the larva either upon bib- 
ulous paper on the table, or upon soft cotton cloth held in the left 
hand, and press the extremity of the body with one finger, always 
with the interposition of cloth or paper, so as to force out any of 
the contents of the rectum ; this process is continued from points 
successively farther back, a slight additional portion of the con- 
tents of the body being gently pressed out with each new move- 
ment ; throughout all this process, great care should be taken lest 
the skin should be abraded by too violent pressure, and lest any of 
the contents of the body soil its exterior or become entangled in 
the hairs or spinés ; to avoid the latter, the caterpillar should be 
i frequently removed to a clean part of the cloth or paper. When 
