PLECTEOTETEA. 285 



Eab. Mexico, Jalapa, Playa Vicente (Hoge). 



It will only be necessary to point out the differences between this species and 

 P. clarki. The former is smaller, with bright metallic green or sometimes blue elytra ; 

 the latter are not so regularly geminate punctate as in the male of P. clarki, but the 

 rows of punctures are more strongly impressed and more closely approached, and placed 

 at more regular distances ; the antennae resemble those of the allied species, except that 

 the first three joints in P. dohrni are fulvous. 



The female is much more difficult to distinguish from that of P. clarki, and the only 

 difference I can find besides the smaller size is the flattened or depressed appearances of 

 the three costse below the middle of the elytra, the space between them having a peculiar 

 opaque appearance, but consisting of finely transverse rugosities as in the allied form. 



The present insect was obtained in great numbers, which all agree in the above 

 structural characters, so that I cannot look upon it as only a variety of P. clarki. 



3. Plectrotetra submetallica. (Tab. XVII. fig. 5.) 



c? . Fulvous ; third joint of the antennae much longer than fourth ; elytra obscure fulvous with a metallic blue 

 gloss, very finely punctate- striate. 



2 . Elytra with short but highly raised costae, interrupted anteriorly and posteriorly. 



Length lf-2 lines. 



Head impunctate, the frontal tubercles very prominent ; antennae nearly as long as the body, entirely fulvous, 

 or with the terminal joints obscure piceous, the third joint much longer than the second ; thorax rather 

 long, about one half broader than long, the sides narrowed from the base to the apex and regularly 

 rounded; surface impunctate, the basal sulcation deep; scutellum fulvous; elytra with a shallow but 

 distinct oblique depression below the base, the latter somewhat raised, surface very finely punctate-striate, 

 the striae very indistinctly arranged here and there in double rows, the interstices not raised. 



Rah. Mexico, Oaxaca, Tuxtla (Salle). 



The peculiar half fulvous, half metallic-blue elytra, their fine punctuation, the colour 

 of the antennae, and principally the distinctly longer thorax, narrowed in front, distin- 

 guish well this species from the preceding ones. The female, which I refer to the 

 same species on account of the same coloration and locality, may be known by the 

 different shape of the highly raised costae, of which three run parallel with the suture 

 at the posterior half of the elytra, but do not extend to the apex nor the base ; at the 

 middle of the disk and close to the three sutural costae is another very short one, 

 preceded laterally by a flattened broad and finely punctured space, the latter of which is 

 again limited near the sides by one or two more elongate ridges. 



Ten specimens, all agreeing in the above particulars, are before me. 



4. Plectrotetra regularis. (Tab. XVII. fig. 6.) 



<£. Pale fulvous; antennae robust, piceous, third and fourth joints nearly equal; elytra fulvous with a slight 

 metallic violaceous gloss, distinctly and regularly geminate punctate-striate. 



Length 3 lines. 



Head impunctate, with highly raised frontal tubercles, deeply transversely grooved behind the latter as usually ; 



