Cassida

Abstract: The genus Eurypedus Gistel is revised based on detailed morphological study, including examination of the mouthparts and genitalia. Besides previously known diagnostic characters, such as an oblong and laterally parallel-sided body, narrow elytral lamella, narrow prosternal process between the procoxae, and angled pronotal base, new diagnostic characters are identified: antennal notches on the ventral surface of antennomeres V–XI, a stridulatory file on the vertex, and paired projections on the ventral surface of the pronotum. The distinct stridulatory file is found only in males. The number of ridges of the stridulatory file varies between 48 and 59. Eurypedus thoni Barber (= Cassida oblonga Sturm in Thon) syn. nov. is synonymized with E . peltoides (Boheman). The remaining two species E. peltoides and E. nigrosignatus (Boheman) show distinct distributions separated by the Amazon Basin.

Abstract: Plant response studies were conducted to determine the effects of feeding by Cassida rubiginosa Muller and mechanical defoliation on the growth and reproduction of musk thistle (Carduus thoermeri W...

Abstract: Cassida rubiginosa Muller is distributed in northeastern North America from southern Canada, southward to northern Virginia and westward to Ohio and southern Michigan. The insect is univoltine in Virginia. The overwintering adults 1st appeared on Carduus nutans L. (musk thistle) during late winter and began to oviposit in early spring. The new generation of adults emerged in late spring and was found on thistles as late as Nov. 1. A laboratory population of C. rubiginosa collected in late winter produced an avg of 815 eggs/female and both sexes lived an avg of 38 wk. Females generally ate more than males. Development from egg to adult required an avg of 20 days at 32.5°C, 26 days at 26.6°C, 41 days at 21.1°C, and 60 days at 17.8°C. The threshold temperature for development from egg to adult was calculated to be 10.4°C. Adults are difficult to sex.