362 ENTOMOLOGICAL NEWS. [Dec, '18 



be readily accomplished, a generic determination is quite diffi- 

 cult. The genus Aphis Linn., as understood by American 

 aphidologists, is an example of this. Macrosiphion Passerini 

 is another. Occasionally one finds a species that does not fit 

 into any genus, or that will fall into any one of a number of 

 genera, according to which table is used for the determination. 

 It is far simpler, and in the writer's opinion better, in such a 

 case, to describe a new genus for that species. 



I. The Genus MACROsiPHONfELLA Del Guercio. 



In 191 1 Del Guercio" described the genus Macrosiphnniella, 

 designating as the type species, Macrosiphuin atrnm (Ferr.). 

 The following species he also placed in this genus: Siphono- 

 phora absinthii Koch, Siphonophnra artcmisiae Pass.^ {tana- 

 cetaria Koch), Aphis campanulae Kalt., Macrosiphoniella 

 chrysanthemi Del Guer., Siphonophora linariae Koch, 5". lutea 

 Buckton, Aphis millcfolii Fabr., A. solani Walker and A. viciae 

 Kalt. "^ 



This genus is quite similar to Macrosiphum Pass., except 

 that the cornicles are not considerably longer than the cauda : 

 in fact they are oftentimes shorter. Del Guercio separates it 

 from Macrosiphum Pass, and Mcgoura P>uckt. by the following 

 key : 



"Sifoni corti presso a poco della liinghezza della codetta: 

 "Sifoni distentamente clavati. ..1/r(/0!/ra Buckton. 

 "Sifoni cilindrici, piu o meno allargati, talvolta. 

 all base Macrosiphoniella Del Guer. 



2 Del Guercio, A. Redia 7: 331-333. 191 1. 



^Theobald (Jour. Econ. Biol., 8: 71. 1913.) credits this species to 

 Boyer de Fonscolombe, and from his description it would certainly 

 fit into this genus. Wilson (Trans. .A.mer. Hnt. Soc, 41 • 97. 1915) 

 describes a species from Artemisia in Oregon under this name. He 

 places 5*. frigidae Oestlund as a synonym. It is probable that he had 

 Oestlund's species, but he could not have had this one, for in his 

 material the cornicles were fully twice as long as the cauda. The 

 measurements were : cornicles 0.73 mm., cauda 0.30 mm. (alate) ; 

 cornicles 0.52 mm., cauda 0.27 mm. (aptera). Therefore Siphonophora 

 frigidae Oestlund is distinct and belongs to the genus Macrosiphum 

 Pass., while 5". artcmisiae Fonsc. belongs to the genus Macrosiphouiclla 

 Del Guer. The latter species has, to date, never been reported from 

 America. 



