456 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 9 



have been dwelling, in this respect differing from the species previously 

 discussed in which the larvse pupate in loose soil or rubbish at the base 

 of the plant. The larvae of Sphccrophoria sulphuripes also pre\' upon 

 the Bean Thrips (Russell, The Bean Thrips, U. S.D. A., Bui. 118, 

 1912). 



Allograpta ohliqua Say is a well known enemy in southern California 

 of the citrus and truck crop plant-lice. Further north the fl> is less 

 common and it has been bred from the walnut aphis {Chromaphis 

 juglandicola Kalt.). A. fracta, a rarer species, is presumably aphido- 

 phagous. The adult flies are rather small. They have yellow cross- 

 bands and in addition longitudinal and obhque yellow markings on 

 the fourth and fifth segments. 



In the allied genus Mesograpta there are two common California 

 species, M. geminata Say and M. marginata Say. These are small 

 species, shining black with yellowish-red abdominal markings. Their 

 economic standing appears to be unknown while the eastern M. 

 polita Say is an injurious form, attacking corn plants and sometimes 

 causing them to wither badly. 



Baccha is a genus of slender elongate flies, in which the body is more 

 or less constricted basally. The larvas of B. lemur Osten Sacken have 

 been bred from the citrus mealy-bug (Pseudococcus citri Risso) ("Mealy- 

 Bugs of Citrus Trees," Univ. Cal; Coll. Agric. Bui. 258, C. P. Clau- 

 sen) and other mealy-bugs (Cal. State Comm. Hort. Mo. Bui., vol. 

 IV, 4, E. 0. Essig) in southern California where the species is common. 

 The larval habits of B. ohscuricornis Loew (? B. elongata), found about 

 San Francisco Bay are unknown. Elsewhere other species of Baccha 

 have been reported (e. g., "Syrphida? of Ohio," Ohio State Univ. Bui. 

 XVII, 31, C. L. Metcalf) as preying in the larval stage upon aphidids, 

 coccids, leaf-hoppers and white-flies. 



The two aphidophagous genera Pipiza and Paragus belong to the 

 tribe Chilosini, a group in which the larvae chiefly inhabit stems and 

 stalks of hollow plants. Pipiza pisticoides Will, and P. albipilosa 

 Will, are rather small, black, shining species and bear much short white 

 pile. They are both common in California and their larvae feed on 

 protected or semi-protected plant-lice such as Pemphigus popidicaulis 

 Fitch on poplar. It is doubtful whether these are of much economic 

 importance but further study might alter this opinion, as both P. 

 modesta Loew and P. radicum Walsh & Riley occur in the East upon 

 the woolly apple aphidid {Eriosoma lanigerum Haus.) and radicum 

 preys also upon the grape phylloxera {Phylloxera vitifolicc Fitch). 

 Pipizce larvffi in California are dark green or greenish-brown and the 

 puparia brown. Both larvae and pupae are somewhat more robust and 

 roughened than those of the Syrphini. 



