9 



erable variation in color, being either 3'ellowish-green with black eye 

 spots and faint stripes, or black with > ellowish spots, as shown in tig- 

 ure 4. They may be readily distinguished from all other caterpillars 

 on cotton by the pointed horn at the end of the body. Occasionally 

 they become excessively numerous and, assembling in great numbers, 

 somewhat like the army worm, destro}' all low-growing vegetation in 

 their path. Such was the case in 1903, when late in Ma}^ serious damage 



C 



Fig. 4. — Deilephila Uncala: a, molli; b, pale larva; c, dark form of larva; d, pupa — all natural 



size (from Chittenden). 



was inflicted on cotton and garden crops in several localities in south- 

 western Texas. 



Life history. — When full grown the caterpillars enter the earth to 

 pupate and the moths emerge about eTuly 1. Usually' most of the 

 ni;)ths fail to emerge, however, as the caterpillars are parasitized by 

 one of the tachina flies to such an extent that but few transform. The 

 second brood is therefore ver}^ small and does no harm. The winter 

 is passed in the soil in the pupal stage. 



Remedies. — The favorite food of these caterpillars is purslane, though 

 many succulent weeds are among its common food plants. Here again, 

 therefore, the destruction of these weeds and thorough winter plow- 



223 



2425— No. 223—05 2 



