C|^ faabian ^ntamobgist. 



VOL. XVIII. LONDON, MARCH, 1886. No. 3 



ON PHYSONOTA UNIPUNCTATA Say, AND ITS SUPPOSED 



VARIETIES. 



BY F. B. CAULFEILD, MONTREAL, P. Q. 



As considerable doubt appears to exist with regard to the three species 

 or races of Physonota described by Say, Randall, and Walsh and Riley, 

 and as I had in former years found a species of this genus to be rather 

 common in the vicinity of Montreal, I endeavored during the past season 

 to find it again, and, as far as my opportunities would permit, work up its 

 life history. 



Early in May I made a careful search in the locality where I had 

 previously found it, but at this date its food plant had not yet appeared 

 above ground. I tried again in June, the time at which I had formerly 

 taken the first brood. The food plant, Heiianthus decapetalus, 'wa.s now 

 about two feet high, but the leaves were untouched, and .to my great dis- 

 appointment no beetles were found, as I particularly wished to ascertain 

 the color of the early summer brood, as those which I had formerly taken 

 at this season were of a bright gold color, quite different from those taken 

 later in the year. This difference of color in the broods appears to 

 me to point to the conclusion that Physonota may possess the power of 

 assuming different tints, as is the case with some other species of the 

 family. On August 15 th I found a colony of the beetles on the same 

 plant, now in full flower. The beetles were all in the autumnal dress, 

 black and white, with testaceous margin. The species is undoubtedly 

 that described by Walsh and Riley as P. quinquepunctata, which is, I 

 think, a synonym of helianthi Randall. This author describes it as 

 having the " elytra blackish, irregularly spotted with white, with a 

 testaceous margin, losing its color after death, becoming nearly pale 

 testaceous, except the three black spots on the thorax." This agrees 

 very well with the species found by me, except that they have a double 

 spot close to the anterior margin of the thorax, but as this fades soon aftef 



