TEEAMEROUS PLANT-BEETLES. 167 



rules which we shall notice below. Labidomera contains one common 

 species, the L. trimaculata^ Fab., found on milk-weed. Myocoryna con- 

 tains the destructive potato-beetle commonly known as the DorypJiora 

 10-lineata, and the allied but much less common species D. juncta, and 

 two other similar species found in Texas and Mexico. The generic 

 name Doryphora, means a spear-bearer, in allusion to the pointed ante; 

 rior prominence of the mesosternum, and was originally applied by 

 Illiger to a similar group of insects from South America. But in our 

 species the mesosternum is not produced to a point, and therefore M. 

 Stal, a Sweedish entomologist, has formed a new genus for them under 

 the name of Myocoryna, from the Greek mus — to compress, and Jcoruna, 

 a club — the club of the antennse being slightly flattened. 



This is one of the exceptional genera with respect to color, being 

 usually striped, but one species is wholly blue, and another is wholly 

 red. Zyr/ogramma, implying literally that the stripes are united or 

 yoJced together, contains a number of common species which are subject 

 to considerable variation. Calligrapha, meaning beautiful icriting, con- 

 tains some of our most elegant beetles, distinguished by the numerous 

 metallic marks and dots on their almost white elytra. The species are 

 numerous and often variable. Mr. Crotch admits thirteen species as 

 iuhabiting the United States ; a few of them depart from the normal 

 style of coloring, and resemble Zygogramma. The organic distinction 

 between the two genera is, that in Zygogramma the claws are approxi- 

 mate and the claw joint toothed beneath ; and in Calligrapha, the claws 

 are distant and the claw joint simple.* Chrysomela j)roper is now re- 

 stricted to a small number of dark colored species, some of which have 

 a golden lustre. One species from Colorado and the neighboring States 

 is black, with a yellow border to the elytra. 



Gastrophyza, Che v., — meaning abdomen inflated — alludes to the re- 

 markably swollen condition of the abdomen of the females when filled 

 with eggs. It contains one of our i^rettiest and most common beetles : 

 the G. polygoni, Linn., common to both Europe and this country. It is 

 three-twentieths of an inch long, of a brilliant blue-green color, with a 

 yellow thorax. It feeds upon the common knot-weed {Polygonum avicu- 

 lare.) Mr. Say described it as a rare insect under the name of Chryso- 



*It is a question whether in grouping certain insects — such, for example, as the Chrysomelides— the 

 plan of coloration should not have more weight, in comparison with slight organic characters. It la 

 evidently unnatural to separate such species, with striped elytra, as elegans, Olivier, and similis, 

 Rogers, from the similarly marked Zyqrogram.ma pulchra and exclarnaUonis, Fab., and conjuncta, 

 Rogeis, and unite them with the dissimilar and dotted group of Calligrapha, upon a character so 

 variable, and therefore unimportant, as is the structure of the tarsal claws, in the whole family of 

 Chrvsomelidif. 



13ut we have been gratified to see, since the above was written, that Mr. Crotch, in his recent Check- 

 list of Coleoptera, has suppressed all these sub-genera, and recognized them only as sections of the 

 original genus Chrysomela, of Linna'us ; a course which, it seema to us, might be profitably adopted 

 with respect to many modern^genera. 



