A. Iv Camkron 63 



vcntro-posteriorly. Basally cacli is perloratcd hy a tiny [(oro. The 

 dentate scleiites which articulate ventrally with the posterior halves 

 of the mandibular sclerites of the larva of Anlhontyia radicum, as Hewitt 

 figures (PI. II, fig. 7, d.s.), are here absent. Articulating posteriorly 

 with the mandibular sclerites are the hypostomal sclerites (h.s.) united 

 to each other by a slender rotl, not evident in a lateral view. Each 

 individual of this pair somewhat resembles a short dirk. Fiom the 

 angle formed by the handle aiul the blade there proceeds a delicate, 

 slender rod (/..'?.) which articulates with the broad, ventral, posterior 

 process of the mandibular scleritc. The proximal extremities of the 

 two hypostomal sclerites articulate, one on each side, with the distal 

 ends of the cephalo-pharyngeal sclerites {c.p.s.) which have each a slight 

 anterior, ventral, ploughshare-like continuation joining on to the hypo- 

 stomal sclerite of its side. The cephalo-pharyngeal sclerites are broadly 

 and deeply embayed posteriorly, thus forming a dorsal {d.]!.) and a 

 stout ventral process {v.j}.). The latter is provided posteriorly with 

 a dorsally directed blunt process. The dorsal arm of the cephalo- 

 pliaryngeal sclerite is itself bifurcate, so that a slender ventral process 

 directed posteriorly underlies the broader dorsal process. Finally the 

 perforate sclerite (pf.s.) situated dorso-anteriorly between the cephalo- 

 pharyngeal sclerites, serves to unite them. In the figure it would appear 

 to be quite detached. This displacement is caused by the pressure of 

 the cover-slip on the mounted preparation from which the drawing was 

 made. Midway between the ventral arms of the cephalo-pharyngeal 

 sclerites there is situated a carinate sclerite of very slender proportions. 

 In Carpenter's figure of the mouth apparatus of the mature larva 

 the cephalo-pharyngeal sclerite is represented as having quite a 

 pronounced rectangular continuation anteriorly, where it articulates 

 with the hypostomal sclerite. This gives one the impression of a fore- 

 shortening of the latter. In reality the suture is placed rather more 

 posteriorly and the apparent continuation of the cephalo-pharyngeal 

 sclerite belongs to the hypostomal. 



9. Comparison with Pegomyia bicolor Wied. and 

 Pegomyia nigritarsis Zett. 



The two allied species P. bicolor and P. itigrilarsis mine the leaves 

 of Rumex ohtusifolius and Riimex crispus in their larval stages, and 

 their life- histories are practically identical and concurrent with that of 

 P. hyoscyami. As imagos all three species have the same general facies 



