59O ENTOMOLOGICAL NEWS. [November, 



The European Pear Scale. 



DIASPIS PIRICOLA (Del Guercio) Saccardo, 1895. 

 BY C. L. MARLATT, Washington, D. C. 



Under the title Chermcs pyri, L/innaeus in his Systcma Xa- 

 iurtF (1758) named an insect which now falls in the Psyllidae. 



More than a hundred years later Boisduval (Ent. Hort., 

 1867, p. 315), under the supposition that he was dealing with 

 the lyinnean insect mentioned, described as Chcrmcs pyri a true 

 coccid belonging to the genus Diaspis. It was a case of mis- 

 identification 011 the part of Boisduval, but, nevertheless, a 

 valid characterization was given to a species not before de- 

 scribed. 



The next reference to this insect is another misidentificatioii 

 exactly similar to the last. Signoret (Essai, 1869, p. 439) de- 

 scribed and figured this Diaspis from specimens found in France, 

 referring it, however, to Aspidiotus ostretr form is described a long 

 time before by Curtis (Gard. Chron., 1843, p. 805). Curtis' 

 insect is an entirely distinct species and a true Aspidiotus, and 

 Signoret' s belief that this Diaspis was the same as the Aspidio- 

 tus of Curtis was based largely on the fact of the identity in 

 food plant, certainly most unsafe ground, and resulting in the 

 same error which similar action on the part of Boisduval had 

 caused a century before. 



On the same faulty reasoning, namely, identity of food plant, 

 Signoret also assigns (1. c., p. 441) the Aspidiotus furfurus 

 Fitch (1856) to the same insect. 



Later also in the same monograph (1876, p. 664) Signoret 

 makes a similar error when he designates Aspidiotus cii'cnlaris 

 Fitch (1856) as another sj^nonym of ostretzformis Curtis as he 

 denominates his Diaspis. Neither Aspidiotus ostreatformis 

 Curtis, a European scale insect recently introduced into Am- 

 erica, nor Chionaspis furfurus (Fitch), the common scurfy 

 bark-louse, nor Aspidiotus circular! s Fitch, which with little 

 doubt is an early name for Aspidiotus ancylus Putnam, have 

 any connection with Signoret' s Diaspis, w T hich he himself 

 points out is the same as Boisduval's pyri (see Essai, 1869, p. 



438). 



The confusion started by Signoret between those various 



