94 Annals Entomological Society of America [Vol.11, 



me by Mr. E. A. Schwarz through the courtesy of Doctor Howard 

 as Scymnus americanus Muls. and Hippodamia i^-ptinctata L. 



The aphids were not attended by ants. This may have been 

 due to the dry time of the year, when, as Professor Wheeler tells 

 me, these insects are not generally so active outside of their gal- 

 leries. It is possible, how^ever, that Aphis atriplicis does not 

 attract ants at any time of the year. Mr. J.J. Davis has found 

 that Sipha flava Forbes is never attended by ants in Illinois and 

 I have noticed the same fact relating to this species in the early 

 summer in Virginia and New York when ants were plentiful in 

 the colonies of other aphids. It is also a matter of common 

 observation that woolly aphids are rarely or never cared for by 

 ants. 



The identification of this species was not difficult on account 

 of its peculiar habits. The original description by Linnaeus is as 

 follows : ' ' Habitat in iVtriplicis littoralis foliis, quae inde revolun- 

 tur longitudinaliter in cylindrum, intra quem vagantur obtectas. 

 Descr. Corpus viride: corniculis minutis. Oculi nigri." It will 

 be seen that this description is less ambiguous than those of 

 many species unhesitatingly referred to Linnaeus, and I prefer 

 to use it to avoid multiplying names. Specimens of the winged 

 and wingless vivipara; were sent to Professor Del Guercio who is 

 familiar with the species in Europe, and he found them to be 

 identical. He placed this species in his genus Ur aphis which is 

 distinguished from other subdiA^isions of Aphis by the cornicles 

 being shorter than the cauda. Since the cornicles are distinctly 

 incrassate, he proposed a new subgenus of Ur aphis, to be called 

 Hayhiirstia Del G. This subgenus would then include all species 

 of Aphis with, incrassate cornicles whi'ch are shorter than the cauda. 

 Del Guercio separates Siphocoryne Pass, from Aphis by the cor- 

 nicles which are "more or less long, clavate." (Nuov. Relazioni 

 R. Stazione di Ent. iVgrar. Firenze (i) No. 2, 1900, p. 142). By 

 general consent those species of Aphis with more or less clavate 

 cornicles which are longer than the cauda have been put in the 

 poorly defined genus, Siphocoryne. In other words, Hayhiirstia 

 Del G. is separated from Siphocoryne Pass, nierely by the length 

 of the cornicles and a supposed difference between clavate and in- 

 crassate. These I consider too indefinite to be reliable generic 

 characters. When forms are found with the cornicles about the 

 length of the cauda, very careful measurements must be taken to 

 determine the genus, and ocular micrometers are not always at 



