SPECIES ATTACKING JOINTS EXTERNALLY. 21 



THE ADULT. 



The adult is a ruoth which expands about 1 inch. It is bright straw colored, 

 with inconspicuous brownish markings arranged in four irregular transverse 

 bands. 



THE LARVA. 



Length, 11 mm. ; shining ; general color yellowish white ; legs concolorous ; head 

 and cervical shield somewhat darker yellow. Sides parallel, except for slightly 

 raised spiracular callosities; faintly impressed median line. Two minute spots 

 on cervical shield and spiracles black. Hairs long, sparse; most numerous on 

 first six segmeuts; white in color; arranged in subdorsal, marginal, and sub- 

 marginal series ; none on median line. 



THE PUPA. 



Inclosed in a whitish cocoon of thin, dense, paper-like construction ; length, 

 9 mm. ; width, 3 mm. ; shining, light brown ; head black. On thoracic segment 

 one median and eight lateral fine longitudinal dai'k lines ; the ones on either 

 side of the median line ai*e double for a short distance near their anterior third. 



SEASONAL HISTORY. 



A generation of this species is produced in about 30 days. The 

 earliest record of the rearing was made by Mr. J. D. Mitchell on 

 May 29 at Victoria, Tex. In that locality the second generation of 

 the year had developed by June 26. The fifth generation matured 

 by September 15. In all probability there is one additional brood 

 during the season in southern Texas. 



DAMAGE. 



The injury by this species is confined to the young joints. Mr. 

 Mitchell has repeatedly seen from 50 to 75 per cent of the new growth 

 destroyed over considerable areas. The moth deposits from one to 

 seven eggs, always on the upper edge of the joint. The first indi- 

 cations of injury are strings of sap exuding from the joints. If this 

 discharge is removed a small hole becomes visible. As the larvae 

 develop the discharge of sap from the plants becomes mixed with 

 silk, trash, and excrement discharged by the insects. (PI. III.) 

 In rare cases, when only a few eggs have been deposited, the joint 

 recovers, although it is always deformed. In most instances, how- 

 ever, decay begins, and the joint turns black and finally drops to the 

 ground. 



The two features of the attack of this insect which cause it to be 

 of great importance in connection with the cultivation of cactus are, 

 first, the large number of broods occurring throughout the season, 

 and, second, the attack against the new growth. Where the species 

 is at all abundant this attack effectually prevents any additional 



