THE SEMITROPTCAL ARMY WORM. 69 
Analysis of 'r~>~>i Misc. 
Per cent. 
Moisture 4. 85 
Total arsenious oxid 40.42 
Total copper oxid 24.87 
Gum and dextrin (approximate) 20. 00 
Acetic acid and other undetermined 0.80 
Total 100. 00 
Soluble arsenious oxid 11.36 
(10 day water ext. method.) 
From the above analysis the sample evidently consists of about 20 per cent 
gum and dextrin and 80 per cent Paris green. The amount of soluble arsenic is 
very high and would undoubtedly give rise to serious trouble. 
SUMMARY. 
The semitropical army worm is a smooth or hairless noctuid 
caterpillar, Prodenia erldania Cram. It feeds normally on weeds, 
such as the pokeweed and spiny amaranth or " careless weed " of the 
South, and is confined to semitropical America as a pest. When it 
becomes unduly abundant it attacks the foliage and, in some cases, 
the stems and fruits of all forms of garden truck growing in its 
habitat, the list of known food plants including tomato, potato, sweet 
potato, eggplant, pepper, okra, collards, and cowpeas. In its habits 
it is similar to the cutworms, having also the climbing habit, and 
when extremely abundant it migrates in armies like the common army 
worm, whence the name. 
Experiments show that the egg period may be passed in a min- 
imum of 4 days, the larval period in IT days, and that the entire life 
cycle, in an outdoor summer temperature, would be about 35 days or 
5 weeks; also, that there are four generations and possibly five pro- 
duced in a year, the insect breeding practically continuously during 
the warm season. In ordinary years the species is largely controlled 
by natural enemies, of which seven are parasitic and six predaceous. 
A series of fifteen experiments was conducted against this species 
in Florida during 1907, which shows conclusively that a spray of 
arsenate of lead is the best remedy, being much superior to Paris 
green when applied under local conditions. It is in every way more 
effective, chiefly becau-e le^s likely to be washed away by the frequent 
rains of the wet season in that region. It is best applied at the rate 
of 2 or 3 pounds in 50 gallons of water, and applications must be 
renewed when the insects again become numerous, as the latter are 
apt to spread from unsprayed plants. 
