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Notes on Chrysomela scalaris, Lee 



By G. \V. J. An(;ell. 



Lately, svhile examining some specimens of the genus Chrysomela, 

 I found an insect answering equally well to the descriptions of sia/ar/s 

 Lee. ox philadelphica Linn. This led me to arrange a series from my 

 material in tnis group, to find, if possible, intergrades between the two. 

 Further examination but strengthened the idea, that these so called spe- 

 cies are but varieties or races of one and the .same insect. Before dis- 

 cussing the series thus obtained I give the original descriptions ofLeconte 

 and Linnitus and also the remarks of Rogers and Crotch. 



"C. scalaris Leconte, Ann. Lye. I, p. 173. 



Oval, greenish blue; elytra punctate, yellowish white spotted with blue. Suture 

 with a broad metallic black stripe, branched in three or four places. Humerus wi;h a 

 large lunate spot; under surface bronzed black, antennae and legs ferruginous." 



"C. philadelphica Linn. Syst. Nat. II, p. 592. 



Oval, greenish black, elytra pale yellow, with a longitudinal stripe near the .sut- 

 ure and a number of dark green spots; palpi, antennae and legs rufous, under surface 

 dark green. ' ' 



Rogers (Proc. Acad. 1856, p. 31) says: "Tliis insect [scalaris) is 

 closely allied to C. philadelphica of Linnaeus, the difference consists in 

 the suture being marked with a broad black stripe with which the spots 

 are connected. In C. philadelphica the suture is black, straight and 

 narrow, separated from a narrow subsutural black vitta by a narrow 

 yellow line."' 



Crotch (Proc. Acad. 1873, P- 4-9) separates them as follows: 



"First vitta joined to suture, which is laterally tridentate scalaris. 



First vitta free, suture not green philadelphica. 



He also states that in this group the epipleura? of the el}tra are 

 yellow. This 1 find to be the case in the majority of insects examined, 

 but it is not entirely constant. From the above descriptions it appears 

 that the basis of all determinations of these insects has been the metallic 

 green, tridentate sutural vitta of scalaris and the free, bronzed, subsutural 

 vitta of philadelphica. In my series I find the following variations from 

 the typical form. For convenience, I refer to those markings near the 

 vitta, which being joined to the latter make it dentate, as vittal spots. 



A. — V'ittal spots small, hardly linear. Humeral markings broken, 

 not forming a continuous line, Vitta faintly marked. An interior 

 humeral spot. 



B. — Vittal spots linear. Humeral markings connected, and two 

 interior humeral spots. Vitta mc>re strongly marked, slightly diverging. 



C. — Vittal spots longer. Humeral line curved and interior spots 

 connected. 



