1 909 J Studies on Aphididac II. 33 



The European Linden Callipterus. 

 [Callipterus {Eucallipterus) tilicu (Linn.)] 



This beautiful aphid I found to be common on the European 

 and American lindens in Chicago parks and in several nurseries 

 in the vicinity of that city. I have been unable to find any refer- 

 ence to this species as having been found in this country, but 

 Mr. J. T. Monell writes that he received specimens of this species 

 from Mr. Theo. Pergande, which w^ere taken on linden at Wash- 

 ington, D. C, May 26, 1886. 



This species was first described by Linnaeus as Aphis tilicB 

 and has since been placed in Callipterus by Koch, in Pterocallis 

 by Passerini, and recently in Eucallipterus by Schouteden. Ow- 

 ing to lack of literature I have been unable to compare the syn- 

 onymy of this genus, and have therefore accepted that given by 

 Schouteden. Likewise the original description of the genus Pter- 

 ocallis is unavailable, but in Aphididcc Italicce, Passerini says 

 of the genus: "Antennee articulo septimo breviore, cseterum ut 

 Myzocallis." The characters given for this genus by Buckton all 

 agree with those of the genus Callipterus, with the possible excep- 

 tion of the triangular fuscous patches at the ends of the veins. 

 The length of the filament of the sixth antennal segment, which is 

 used in separating Pterocallis, is an uncertain character, and- of 

 no generic value in itself, for the length of this portion of the sixth 

 segment may vary from an extremely long filament, as in Callip- 

 teriis betulcecolens, to one subequal to the basal portion as in C. 

 trifolii Mon. 



Mr. Monell has called my attention to a note by Buckton which 

 illustrates the instability of the genus under discussion. Under 

 Pterocallis juglandicola, Buckton* says: 'On account of the 

 size of the seventh antennal joint, possibly this species might be 

 ranged under Callipterus; I leave it, however, where Passerini 

 has placed it." Although C. tilicu differs slightly from the typical 

 Callipterus, it does not seem sufficiently characterized for a sep- 

 arate genus, and I therefore retain the genus Callipterus with 

 Eucallipterus as a possible subgenus. 



The habits of this species agree in every respect with those 

 of the genus Callipterus. This year (1908) the sexual forms were 

 found as early as September 15. 



* Buckton, G. B. Monograph of the British Aphides, London, Vol. Ill, 

 1880, footnote, p. 3:3. 



