DROSOPHILID^ WITH PARASITIC LARVit I65 



DROSOPHILID^E WITH PARASITIC LARVi^ 



(Dip/era) 

 By FREDERICK KNAB 



The two species of Drosophilidae herein described have been reared 

 from larvae feeding upon other insects. One of them, Gitonides perspi- 

 cax, has been reared no less than four times, independently, from larvae 

 found feeding upon mealy bugs (Pseudococcus) . The second form, 

 Titanoch&ta ichneumon, was reared from larvae feeding upon spider's 

 eggs. The form preying upon Pseudococcus proves to be closely related 

 to the genera Gitona and Acletoxenus, which, it appears, have larvae with 

 similar habits. The European Acletoxenus formosus has been reared by 

 Walker from larvae preying upon A leurodes philh^rea Hal. on Crat&gus 

 and later by von Frauenfeld from the same host as well as from A leu- 

 rodes jelineki Frf. on Viburnum} Gitona distigma of Europe, accord- 

 ing to Kaltenbach, has been reared by Loew, and also by Scholz, from 

 flower-heads of Sonchus arvensis.^ As plant lice are known to occur in 

 large numbers on the upper part of this plant (vide Kaltenbach, p. 39 7), 

 there is every reason to believe that the larvae of Gitona prey upon these. 

 In Gitona, Gitonides, and Acletoxenus we have, then, three closely 

 related genera with similar larval habits. The second new form, Titano- 

 ch&ta, is remarkable for the strong development of its macrochaetae and 

 shows no close relationship with the three genera above discussed. 



Gitonides, new genus. 



Frons about one-third the width of head. PostverticcJ bristles con- 

 vergent ; three pairs of orbital bristles, inserted close to eyes, the anterior 

 pair proclinate ; oceUcir bristles very stout, equaling orbital bristles in size, 

 proclinate ; inner vertical bristles strongly convergent, outer verticals diver- 

 gent. Face not distinctly keeled, the oral margin not produced ; cheeks 

 rather broad, wath a row of small bristles ; vibrissae well developed, 

 strongly differentiated. Eyes large, naked. Antennae rather stout, the 

 third joint broadly leaf-like ; arista long, microscopiceJly ciliate. Thorax 

 moderately convex ; prescutellar bristles present ; one pair of strong dor- 

 socentrals, a second weak pair sometimes present ; notopleural bristles at 



'Walker. List Homopt. Ins. Brit. Mus.. iv (1852), p. 1093, and Insecta Brittan- 

 ica, Diptera, vol. 2 (1853), p. 243 (as Agromyza ornata); v. Frauenfeld. Verh. 

 zool.-bot. Ges. Wien. vol. 18, p. 150 (1868). 



^Pflanzenfeinde, 1874. p. 396. 



