12 Department Circular 288, U. S. Dept. of Agriculture. 



especially those of a generalized nature.^ It appeal^ that when a 

 caterpillar is pressed against the skin some of the spines, which are 

 hollow, break off and others are pulled out. Beneath the clusters of 

 spines apparently there are glands which secrete a poison which 

 passes up within the spines, much as described by Packard in the 

 related species Lagoa crispata Pack.* The poison glands of the 

 brown-tail moth have been studied b}' Kephart ° and investigations 

 on the nature of the venom in that species have been carried out by 

 Tyzzer.^ 



NATURAL CONTROL. 



It is fortunate that, in Texas at least, some very effective natural 

 control agencies are at hand. In fact it is difficult to rear larvae to 



Fig 9. — Cocoon of puss caterpillar with exuvia; protmdiug after 

 emergence of moth. 



maturity on account of the high mortality among them due to a 

 bacterial disease, usually manifesting itself among larv?o which are 

 half grown or larger. They become sluggish and cease to feed. After 

 a few days they die and become very soft, a typical result of bacterial 

 infection. Specimens sent to Dr. G. F. Wliite, of the Bureau of 

 Entomology, were found to contain two distinct species of Micro- 

 coccus, but he could not state positively that they were responsible 

 for the mortality among the larvir. In many instances this disease 



3 Since this paper was prepared Dr . N . C . Foot has published some results of experiments with Mrgalopyge 

 opcrcularis (Jour. Exp. Med., v. 35, p. 737-753, May 1, 1922). Ho found that injections into rabbits and 

 mice of an extract of ground caterpillar skins and spines produced marked symptoms and even 

 death. He concludes that, "The poison appears to be of the nature of a venom, combined with protein 

 vehicles, and may be itself a protein." It is rendered inert by boiUng. 



* Packard, A. S. A study of the transformations and anatomy of Lagoa crLtjxita Pack., a Bombycine 

 moth. Proc.Amer. Phil. Sbc.,v. 32, p. 275-292, 7 pi., 1S9}. 



5 Kephart, CorneUa F. The poison glands of the larva of the brown-tail moth, Euproctis chrysorrhoea 

 Linn. Jour. Parasit., v. 1, p. 9.V-I03, illus., December, 191 \. 



6 Tyzzer, E. E. Thepathologv of the brown-tail moth dermatitis. /ft2d Ann. Rpt. Sup t. for Suppress- 

 ing the Gypsy and Brown-tail Moths, p. 154-108, Boston, 19()7. 



