24 ; PARASITES OF THE COTTON BOLL WEEVIL. 
The first type was a cubic cage made very easily by using strips of 
cork for the framework and fine meshed wire (known as 50 to the 
inch, but really 35 and 45 to the inch) for the sides. One side was 
fixed with two openings which were closed on the inside by a tin 
shutter. The lower opening was round, and in this a cork with a 
glass tube through it was placed before the shutter was raised. 
Thus the parasites, being attracted to light, could be quickly removed 
by darkening the sides and allowing the light to enter only through 
the tube. When the shutter was raised higher it exposed a larger 
opening through which material could be passed. 
With this first cage as a type various modifications were contrived, 
all with wire fronts, shutters of various kinds, and corked holes for 
the admission of a tube or for passing in small objects. Cigar boxes 
became the bases for these cages. 
Still another modification was a wire cylinder corked at one end 
and with a smaller cork centered in this for the removal of material. 
The other end was covered with cheese cloth. 
It was found impossible to provide plant conditions in a small 
cage unless the plant were actually transplanted or grown from 
seed. “A branch of cotton withers so quickly that experiments of 
this sort were of no value. 
Both kinds of tubes were tested on the plants, but the mica tube 
caused a heavy sweat and killed the branch it was on; the wire tube 
was too heavy. All of the plants placed under the large parasite- 
tight cages with glass sides died before results could be expected. 
2. FIELD WORK—RELEASE OF PARASITES. 
The release of parasites in the field was not commenced until 
September 12 on account of the small amount of material gathered 
prior to that date. Notwithstanding that fact the results give an 
indication of success. On the laboratory farm at the top of the hill 
there were released 35 parasites on September 12 and 38 on Septem- 
ber 15. These parasites were of three species. An examination of 
hanging forms was made in this part of the field and another down 
the hill at the opposite side and about 350 yards distant. At this 
time the check area (‘‘B,” fig. 5) showed 1.9 per cent higher para- 
sitism than the parasite area (‘‘A,” fig. 5). Twenty days later, on 
October 2, like examinations were made with the result that the 
percentages were reversed; ‘“‘A’’ showed an increase of 2.6 per cent 
and ‘‘B” showed a decrease of 6.5 per cent; that is, “A” was 7.2 
per cent more highly parasitized than ‘‘B” and showed a real gain 
in parasitism of 9.1 per cent. On October 6 this examination was 
followed by another, and, although the difference was less, “A” was 
3.9 per cent more highly parasitized than ‘“B.” Plat “A” was next 
to a fence and separated from another field of cotton by a road and a 
