THE COTTON STAINEB. 3 



{Urena lohata), and nightshade {Solanum nigrum). Observations 

 made in the vicinity of Orlando, Fla., by Dr. A. W. Morrill, indicate 

 that the Spanish cocklebur is probably the most important of these 

 plants. 



DAMAGE. 



From observations made in the Bahamas in 1878, Mr. E. A. 

 Schwarz concluded that this species is an enemy of cotton of very 

 great importance in those islands. In Florida the damage is scat- 

 tered and naturally difficult to estimate. In one instance, pointed 

 out by Dr. Morrill, the complete destruction of 25 acres of long-staple 

 cotton was attributed to this insect. Generally, however, the injury 

 does not extend further than the staining of a portion of the crop 



Fig. 2. — The cotton stainer: a, Fourth-stage nymph, or pupa; b, adult. Enlarged. 

 (From Insect Life.) 



produced on the plantation. A case referred to by Dr. Morrill ^ is 

 undoubtedly typical. In this instance at Hawthorn, Fla., in 1902, 

 about 1,000 bales of long-staple cotton were ginned at a certain 

 establishment. Out of this number 200 bales were classed as stained. 

 Staining reduces the value of the cotton in varying degrees, running 

 from 50 per cent in severe cases down to 5 or 10 per cent. 



It has generally been supposed that the staining of the fiber was 

 due to the excrement of the insect, but Dr. Morrill's observations 

 in Florida seem to indicate that this is not the true explanation. 

 From studies in the fields and experiments in rearing cages he came 

 to the conclusion that the staining of the lint is the result of the 

 attack of the insects upon immature bolls, and especially on the seed 



I Bui. 86, Bur. Ent., U. S. Dept. Agr., 1910, p. 97. 



