PK(»MFKK.\TI<)X FOLLOWINC ATTACKS (>F FrN(iI. 2'> 



STIMULATION TO PROLIFERATION BY CAUSES OTHER THAN 

 WEEVIL ATTACK. 



I'KOMFKU vrioN STIMl I.ATKl* MV OTIIKU INSFX'TS. 



Since l)(',i:iiiiiiii<.; this study of prolitrrat ion it has hccn noticed 

 frc(|iiciit ly that it oi-curs coniiiioiily in locahtics where liie weevil is 

 not found and from numy other inciting causes. Some of tlie most 

 ahun(hinl j)roHfenitions have heen fonnd in holls antl squares foIh)\v- 

 in^ the attack of youn^- hollworms {Ilcliot/iis ohsoleta Fab.). (See 

 PL II, figs. 5, G.) In many cases small columns of purely proliferous 

 material have heen found |)rojected from the j)unctures made by the 

 pressure i)roduced within the square or holl. Similar cases resulting 

 from the attacks of young square-borers — {'ranotes inelinuf< Ilbn. (PI. 

 II, fig. 7) or t)tlier Thecla larva' — are to be found in a probably larger 

 proportion of the cases of attack than is generally true with weevils. 

 Many species of bugs connnonly produce proliferation of internal 

 tissues in bolls, though ut) mark of their puncturi' can be seen in an 

 external examination of the boll (PI. Ill, figs. 8, 9). In this way a 

 Mexican bug (Pentatonia ligata Say) does great damage by inciting j)ro- 

 liferation in the seeds (PI. Ill, figs. 10, 11) and preventing the ojiening 

 of the boll. In a series of examinations covering 4,000 punctures made 

 by this bug 34 per cent of the punctures were found to show distinct 

 l)roliferation. A number of species of native bugs hav(> been found to 

 incite proliferation in a similar manner. Leptoglossus phyllopus L. 

 and Xezara /n7an.s- Say have ])een studied especially, and ))roliferation 

 has i)een found in a large percentage of |)unctures made by these 

 species. In the fields the injury of several species is likely to be so 

 similar in nature and effect as to make it im|>ossible to sejiarate the 

 work t)f the various species concerned. Thus Kuscliistus s(rvus Say, 

 Nf'zara hilans Say, and Thyanta custator Fab. commonly occur 

 together. In an examination of bolls attacked by these three species 

 proliferation was found in 52 per cent of the total number of locks 

 examined. Other species of Leptoglossus, especially L. oppo.fitus Say 

 and L. zomitits Dall., have frecpn^ntly been taken upon cotton, and 

 undoul)tedly they incite proliferation exactly as L. j>/njll<>pus is known 

 to do. Lnrgus succi7}ctus L. also feeds u|)on cottcm bolls and in all 

 probability incites proliferation, although specific instanc(>s have not 

 been observed. 



PROLIFEKATION STI.MII,ATKI> HV AITAC KS OK KINCI. 



In examining large s(>ries of bolls it was found thai a >mall per- 

 centage showed distinct and characteristic proliferation on the inner 

 side of carpels, which W(>re severely attacUed externally by a fungous 

 disease of cotton known as anthracnose. No other cause for the jiro- 

 liferation could be seen, and the numbei- of obsi-rvations leaves 



