INTRODUCTION. 
The present bulletin consists of a report made by Mr. F. TV 7 . Mally 
upon the progress of the special investigation of the Cotton Boll-worm 
which has been carried on under the Division since the appropriation 
became available, July 1, 1890. Mr. Mally has had charge of the minor 
details of the investigation, and has been constantly in the field since 
last July. He also summarizes the results obtained by Messrs. Mc- 
Neill and Booth. The Boll Worm was treated at some length in the 
Fourth Report of the U. S. Entomological Commission, and the chief 
object of the present investigation was to conduct further experiments 
with remedies, as well as to verify the value of those already employed. 
A thorough series of experiments has been planned with the diseases 
of Heliothis and allied insects, in the hope of being able to practically 
utilize them. Incidentally I have desired to ascertain new facts, if 
possible, and to verify or disprove what has been previously written in 
connection with the life history and habits of the species. 
The observers have all been hampered in their work by the unexpected 
lack of material. The funds were not available until the season was 
three-fourths spent. The observations so far made will, therefore, have 
to be supplemented the coming spring and summer. It transpires that 
the ravages of the Boll Worm have been overestimated, and that while 
from 20 to 30 per cent of the bolls are damaged in an average season in 
Mississippi, onlv about one-third of this damage is done by this insect. 
Several other species which do work somewhat similar to that of the 
Boll Worm are treated in this report. Some new food-plants have been 
found, and a careful study has been made of the habits and life history 
which are here treated with more care and detail than has heretofore 
been given to the subject. Two new parasites have been discovered, and 
observations have been made which show that the egg parasite (Trich- 
ogramma pretiosa Riley) is an extremely important factor in the economy 
of this insect, as it is, also, in that of the Cotton Worm (Aletia xylina 
Say), and the Grass Worm or Fall Army Worm (Laphygma frugiperda 
Smith & Abbott). A careful count shows that 84 per cent, of the eggs 
were destroyed by this useful parasite. All of the old remedies have 
been once more tested, and the use of corn as a trap crop is again shown 
to be one of the most satisfactory means of protecting the cotton crop. 
The old subjects of attracting the moths to lights and poisoned sweets 
have once more been carefully considered, aud my former conclusions 
have been confirmed, that there is little to be hoped for from either of 
these methods. The pyrethrum experiments, from which I had much 
