48 



The general appearance of the female is .sliown in figure 16 at r/, much 

 enlarged, the segment.s of the antenna? being shown still more enlarged 

 at 1). The genitalia or sexual organs of the male are illustrated, also 

 greatl}^ enlarged, at c. 



DISTRIBUTION. 



It seems probal)le that this species, like others found in gi'eenhouses, 

 and in habitations, storehouses, and indoors generally, has I)een intro- 

 duced from abroad; and it is perhaps tropical, at least in origin. The 

 present known distribution includes the following localities: Wash- 

 ington, D. C. ; Richmond and Gordonsville. Va. ; Nyack, Tappan, and 

 Cornwall-on-the-lludson, N. Y. 



FiG. l(i. — DipUiMs riolirola: (t, IVmale fiy; /), fciiiiiU' iiiiteiinal joints; c, male genitalia: d, larva; c, 

 breastbone of larva — '(, h, iniicli enlarged; c, d, c, more en!arge<l (from Coqnillettj. 



This species lirst attracted attention in 18l)(>, when it was noticed by 

 Mr. Dorsett on sweet violets in the vicinity of Washington, D. V. One 

 of our correspondents, Mr. W. V. V. Powers, writing under date of 

 Januaiy i;JT, 1899, stated that he had noticed this insec-t three years 

 earlier, and although he could not feel certain that tliere was any con- 

 nection between the a})pearance of this pest and the introduction of 

 the so-styled California violet, it was noticed that they ])oth appeared 

 the same year in his \'icinity, Gornwall-on-the-Hudson, N. Y. 



NATURE OF INJURY. 



The maggots, as previously stated, conceal themselves in folds of 

 the young, growing leaves, causing a distortion or curling into irregu- 



