THE BOLL WORM REMEDIES. 
377 
Under this bead of predaceous enemies we may properly mention He- 
liothis itself, but we have already given particulars of its cannabalistic 
habits. 
It was thought for a long time that the Boll Worm was absolutely 
free from true parasites, but this has been proved untrue. Three spe- 
cies of parasites have been bred and undoubtedly more will be found. 
In 1872 we bred Tachina anonyma Eiley from Heliothis armigera, and 
mentioned the fact in a foot-note to page 129 of our Fourth Missouri 
Entomological Report. In 1879 the species of Tachina which we have 
described as Tachina aletia; {Canadian Entomologist, XI, p. 162), and 
which is also, as the name implies, an important parasite of Aletia, was 
bred at the Department from a Boll Worm collected at Selma, Ala., by 
Mr. Trelease. The white eggs of this Tachina have also been observed 
by Mr. Hubbard at Crescent City, Fla., by Judge Johnson at Holly 
Springs, Miss., and by Prof. K. W. Jones at Oxford, Miss. The latter 
says v 
In the latter part of the Reason a great many larva; of Heliothis and Aletia bore a 
white which was found to he Tac hina. In some instances the moths hatched out 
not withstanding the eggs of the parasite. In other cases the chrysalis was destroyed 
by the grub ; the latter was generally the case. Sometimes as many as five eggs of 
Tachina would be found on one larva of Heliothis or Aletia ; more generally on Ale- 
tia than Heliothis. This Tachina must be an exceedingly formidable enemy of both 
Aletia and Heliothis. 
It is interesting to note that Tachina eggs were observed on Boll 
Worms many years ago. Mr. J. W. Boddie, writing in 1850, says (see 
Bibliographical List): "I cannot account for their disappearance, for 
the season was favorable. They may have been destroyed by some of 
the Ichneumonidai family, perhaps the white oblong dots we saw on them. 
I never saw them on the first brood or their eggs." 
The remaining parasite is also one which is common to Aletia. It is 
the Trichogramina egg-parasite, Trichogramma prctiom Riley (see page 
102). It was bred by Mr. Hubbard from the eggs of Heliothis at Cres- 
cent City, Fla., and the specimens sent were accompanied by the note: 
"Eggs of both Aletia and neliothis parasitized turn black on or by the 
second day; the Chalcids disclose about 7 or 7 J days from the time the 
eggs are stung." The only point in which the parasitism of the eggs 
of the Heliothis will be found to differ from that of Aletia eggs is that, 
owing to its greater capacity, the egg of Heliothis will probably sus- 
tain more of the parasites. 
REMEDIES. 
Under the head of remedies we may briefly mention in the first place 
two plans which have had strong advocates for many years. These are 
topping the cotton and rotation of crops. The first of these plans has 
been followed by many planters, but it is an easy matter to show, as has 
been done with Aletia, that the number of eggs laid upon the part of 
