ILLUSTBATIONS. 13 



Page. 

 Plate XTV. Natural control of the boll weevil, a, Pilose and nonpilose stems 

 of cotton; b, larva of boll weevil crushed by proliferation; c, 

 pupaof Catolaccus incertus on pupa of cotton-boll weevil; tf, larva 

 of Microbracon mellitor attacking boll weevil larva; c, /, holes 

 gnawed by Solenopsis geminata in effecting entrance into in- 

 fested squares 120 



XV. The difference between hanging and fallen squares. Fig. a. — 

 Cotton squares with short absciss layer, permitting infested 

 squares to fall. Fig. b. — Cotton squares with long absciss layer, 

 retaining infested forms to hang and dry 136 



XVI. Boll weevil ants, a, Eciton commutatus; b, Cremastogaster lineo- 

 luta; c, Dorymyrmex pyramicus; d, Monomorium pharaonis; c, 



Solenopsis molesta; f, Iridomyrmex analis 140 



XVII. Boll weevil parasites, a, Eurytoma tylodermatis, male; b, Eury- 

 toma tylodermatis, female; c, MicrodontOTnerusanihonomi, female; 

 cf, antenna of same; d, JSabrocytus pierced, female; d' '. antenna 

 of same; e, Catolaccus hunteri, female; c' , antenna of same; /', 



antenna of Catolaccus incertus 140 



XVIII. Boll weevil parasites, a, Lariophagus texanus, female; b, emer- 

 gence hole of Tetrastichvs hunteri from weevil larva; c, Tetra- 

 stichus hunteri, female; & ', antenna of same; d, puparium of 

 Ennyomma globosa in weevil larva; c, Ennyomma globosa; f, 

 ( 'erambycobius cyaniceps, female;/', natural position of same.. 144 



XIX. Effect of Paris green on cotton. Fig. a. — Cotton before treat- 

 ment with Paris green. Fig. b. — Cotton one week after treat- 

 ment with Paris green 148 



XX. Cultural control of the boll weevil. Fig. a. — Early fall destruc- 

 tion of stalks, the fundamental method for controlling the boll 

 weevil. Windrowing stalks for burning. Fig. b. — Chain cul- 

 tivator passing through cotton rows 152 



XXI. Use of chain cultivator. Fig. a. — Space between cotton rows 

 before passage of cultivator. Fig. b. — Effect after passage of 



cultivator 152 



XXII. Results of early and late planting of cotton. Fig. a. — Late- 

 planted cotton under boll-weevil conditions, given same cul- 

 ture as early planting. Fig. b. — Early-planted cotton adjoining 

 the late planting under same conditions 160 



TEXT FIGURES. 



1. Map showing the distribution of the cotton-boll weevil on January 1, 1912. 20 



2. Map of portion of Texas, showing movement of the center of cotton produc- 



tion west ward 25 



3. Secondary sexual characters of Anthonomus grandis 37 



4. Cotton-boll weevil: Head showing rostrum, with antennae near middle and 



mandibles at end; mandible 39 



5. Diagram showing average activity of five female boll weevils 59 



6. Diagram to illustrate influence of temperature on average rate of oviposition 



of boll weevil 60 



7. Diagram illustrating relationship of temperature to the egg period of the boll 



weevil at Victoria, Tex., in 1902 63 



8. Diagram illustrating relationship of temperature to the egg period of the boll 



weevil and showing variations due to humidity 64 



9. Diagram illustrating relationship of temperature to larval period of the boll 



weevil and showing range due to humidity 66 



10. Diagram illustrating relationship between temperature and the pupal 



period of the boll weevil and showing variations due to humidity 67 



11. Diagram illustrating effect of time of falling of infested squares upon period 



of development of boll weevil at Victoria, Tex., August, 1904 70 



12. Diagram illustrating temperature control of developmental period of the 



boll weevil 71 



13. Diagram illustrating normal developmental period of boll weevil in squares, 



by months, at Victoria, Tex., Ardmore, Okla., and Vicksburg, Miss 71 



14. Diagram illustrating seasonal history of the boll weevil at Victoria, Tex. . . 75 



15. Status of the boll weevil in Texas in August, 1906; percentage of infestation 



of all forms 79 



