Entomological Society. 5641 



the excellence of the tarsal system. This division contains the great mass of vege- 

 table-feeding insects, consisting of the three great families of Longicorns (Cerambyx, 

 Linn.), with a long, body and loug, straight antennae; the weevils (Curculio, Linn.), 

 with a short body and generally elbowed antennae; and the Phytophagous beetles 

 (Chrysomela, Linn.), with a short body and short, straight antennae. The intimate 

 connexion between the families Curculionidae and Chrysomelidae was proved by such 

 genera as those described by Lacordaire, as Phytophagous ; and by Schonherr, as 

 Curculionideous; as well as by Carpophagus and Rhaebus ; whilst the connexion be- 

 tween the Longicorns and Chrysomelidae was effected by the Australian genus belong- 

 ing to the Acrocerides, but having entirely the appearance of the Lepturides, as well as 

 by Donacia and its allies. All these insects, from the nature of ther mode of life on 

 plants, require a firm footing, and their tarsi are consequently dilated, and furnished 

 beneath with pads. This is the case with the three basal joints; but the fourth joint, 

 either on account of the large size of the three preceding joints, or in order to 

 strengthen the terminal claw-joint, was of a very small size, and was generally sol- 

 dered to the base of the claw-joint. Here, then, could be no doubt that the fourth 

 joint was becoming, as it were, obliterated ; so that it would be easy to conceive a 

 pseudotetramerous insect in which the soldering of the two terminal joints had be- 

 come so close that all trace of the articulation would be lost ; and if this occurred 

 simultaneously with the narrowing of the basal joints we should have before us the 

 hind-foot of a heteromerous insect. The insect under examination presented a dif- 

 ferent mode of the gradual top of a joint. The tarsi consisted of a short joint, rather 

 swollen at the base of the foot, having several bristles placed obliquely at its extremity 

 beneath. This is followed by a long, simple joint, obliquely truncated at its tip, with 

 several bristles inserted obliquely at its extremity beneath, and having a very indis- 

 tinct trace of articulation across the middle ; it is nevertheless, however, furnished on 

 the under side, at the point where this central articulation should take place, with one 

 or two fine bristles, like those at the extremity of the basal joint. There then follows 

 a small but distinct joint, at the end of which the long claw-joint is fixed. Here, 

 therefore, the apparent loss in the number of joints was caused by the soldering toge- 

 ther of the second and third normal joints. In its general form, and the number of 

 joints and form of the antenna?, the insect is closely allied to the genus Orthoperus ; 

 there are, however, certain modifications of structure in the palpi which require fur- 

 ther examination before we can definitely refer the insect to that genus. It was, how- 

 ever, important to determine what bearing this structure of the tarsi would have upon 

 that of the genus Orthoperus, more especially since it was from various observations 

 on this part of the structure of that genus that it had been regarded as a separate ge- 

 nus by Heer, who had named it Pithophilus, and by Redtenbacher, who called it 

 Microsphaera. On examining some specimens of the legs of the common British spe- 

 cies of Orthoperus, mounted in Canada balsam by Mr. Wollaston, we found the same 

 general proportion of the joints; but the articulation between the short basal joint and 

 the long second joint was almost lost; whilst the almost obsolete aiticulation in the 

 middle of the long second joint, in the Madeira species, was quite distinct, the two 

 terminal joints being alike in both. Although, however, the basal joint appeared lost 

 by coalition with the second joint, there still remained evidence of its existence, in the 

 presence of a small, oblique bristle on the under side of the foot, just where the ex- 

 tremity of the basal joint might be looked for. The two structures, therefore, illus- 

 trated each other, proving that these insects, and also leading to the belief that many 

 XV. 2 Q 



