126 
experiments were conducted in a crude way, without the use of special 
bacteriological apparatus, and are, of course, open to question. Thev 
tend to show, however, the bacterial nature of the disease, the presence 
of a specific organism, and the possibility of contagion. 
Another observation serves to show the contagious nature of the 
disease. It was noticed on August 15, iOOl, that four larvae had died 
in succession in as many nights in the same breeding jar, the dying 
bollworms having been daily replaced by new ones. At this time a 
thorough washing with hot water and soapsuds prevented future mor- 
tality^ in the jar. We have noted man}^ other similar instances during 
the breeding work. 
Quite often the larva has already entered the soil before it is appar- 
entl}^ attacked, and, again, not infrequently a larva may die while in 
the act of constructing its burrow. 
It is very noticeable that larvae which have been injured or bitten 
by their fellows are much more susceptible than healthy specimens; 
in fact, a larva which has been but very slightl}^ hurt scarcely ever 
escapes infection. 
At present there seems to be no hope of making any practical use 
of the disease in controlling the bollworm, as has been done with some 
other species of injurious insects. It is an important factor, however, 
and helps to keep the pest in check. 
SCAVENGERS FOLLOWING THE BOLLWORM. 
In addition to the true parasites of the bollworm there are a num- 
ber of insects acting as scavengers, some of which are often mistaken 
for parasites. 
On numerous occasions we have observed minute flies, belonging to 
the family Phoridfe, hovering about the breeding jars which contained 
specimens of larvae, pupee, and adults; in fact, it is almost impossible 
to keep large numbers of bollworms or pupae together without attract- 
ing these little scavengers. In one case the Phorida? were allowed to 
oviposit upon aHead and decaying moth, and after a period of seven- 
teen days the adults of a second generation appeared. They proved to 
be AphiocJiBeta fungicola Coq. In other lots of larvae from various 
localities many speicimens of Phora hicisufrdis Loew were obtained 
at different times during the summer, and doubtless other species 
might have been found if special search had been made for them. 
Aphlochdeta nigriceps Loew {Phora aletise Comst.) has been observed" 
to feed upon the dead pupae and adults in the same way, and was at 
first thought b}^ Comstock^ to be a true parasite. This has been 
abundantly disproved, however, and none of the species have any 
especial economic significance, since they never attack living boll- 
worms in any stage. 
oEiley, Fourth Kept. U. S. Ent. Com., p. 117. &Eept. Cotton Ins., p. 208. 
