A Systematic Study of the Anthomyiinae of New York 59 



tuft, as in Pegomyia calyptrata, P. hyoscyami, P. fringilla, and P. vanduzeei. 

 Occasionally the bristles may be absent on certain parts, as in Pegomyia 

 calyptrata and P. affinis. In still other species, as Hylemyia setitarsata, 

 Pegomyia lipsia, P. affinis, and Eremomyia vernalis, the integument may 

 be perfectly smooth; or it may be entirely spinulose, as in Pegomyia 

 ruficeps and P. calyptrata. Frequently only certain terga or sterna (foi 

 example, in Pegomyia unicolor, P. dissecta, and Hylemyia betarum), or 

 only certain parts of either sternum or tergum (as in Pegomyia hyoscyami, 

 P. littoralis, P. fringilla, Hylemyia fugax, and Hammomyia spp.), may be 

 covered with minute spinules. The ninth sternites of Pegomyia winthemi 

 and P. fiiscofasciata are clothed with fine, short hairs. 



The lateral conjunctivae are extensive on all segments except the tenth, 

 on which they have become unrecognizable as such due to the modification 

 of the anal plates. The surface of the conjimctivae may be smooth, entirely 

 spinulose, or partly smooth and partly spinulose, either collectively or 

 individually. In this respect the membrane may conform to or be inde- 

 pendent of the character of the tergum and the sternum immediately 

 adjacent, as in Hylemyia cilicrura, Pegomyia rubivora, Anthomyia pluvialis, 

 and other species. Frequently the conjunctival membrane may be rough- 

 ened by tubercular thickenings or ridged lamellations of chitin, as in 

 Hylemyia lasciva and Paregle radiaim. 



The intersegments 



The intersegments are homologous to the transverse conjunctivae of 

 the preabdomen. They are frequently equal in extent to the segments 

 themselves, functioning as a membranous sheath for the inclusion of the 

 segments when at rest, and acting as a telescopic extension for the length- 

 ening of the ovipositor when in operation. In a few forms, notably among 

 the leaf miners, the intersegments are reduced to narrow, transverse 

 membranes, as in Pegomyia calyptrata, P. vanduzeei, P. fringilla, P. 

 hyoscyami, and P. ruficeps. Intersegment 9 is reduced considerably 

 in extent; on its ventral surface the membrane merges imperceptibly into 

 that surrounding the genital opening. 



The intersegmental membrane may be entirely smooth, as in Pegomyia 

 affinis, P. unicolor, Hylemyia innocua, H. setitarsata, Eremomyia vernalis, 

 and Calythea albicincta; or it may be entirely spinulose, as in Pegomyia 

 ruficeps, P. hyoscyami, P. fringilla, Hylemyia pluvialis, H. betarum, and 

 H. cilicrura ; or it may be partly smooth and partlj" spinulose, as In Pegomyia 

 fiiscofasciata, P. littoralis, P. urinthemi, Hylemyia depressa, and Paregle 

 radicum, either collectively or individuaU3^ In certain species the spinules 

 may overlap the adjacent membranes or sclerites, as in Pegomyia winthemi, 

 P. fiiscofasciata, P. littoralis, and Hylemyia depressa. 



Like the conjunctivae, the intersegmental membrane may be roughened 

 by chitinous granulations, which may or may not be spinulose, as in 



