IS^o.] 227 



Amthizoa Lee. (Fam. nova ?) 



Pedes ambulatorii, tarsi pentameri, articulo ultimo valde elongato ; antennae 

 11-articulatae, liliforines, glabrae; palpi breve-; cylindrici ; maxillae lobo interiore 

 arcuato acnto, e.vteriore biarticulato, palpifornii ; prosternum postice productum, 

 obtusu.r;; coxoej anticE et interriiinliae parv;e, olobosae, postica? transversae ad mar- 

 ginem corporis extensnp ; abdomen t>-articulatum, articulis 3 primis connatis. 



After repeated comparisons v^'ith };enera of all the families to which this in- 

 sect seems allied, it has been found impossible to place it in any of the pre- 

 viously established irrouj)s. A full discussion of the comparative value of the 

 characters ottered by it, would involve an examination of the fundamental prin- 

 ciples of clas>i(icarion of the terrestrial and aquatic predacious beetles ; the ma- 

 terial for such a discussion is not yet available in this country, and it must 

 therefore be postponed to a future occasion. For the present, a few observations, 

 on some heretofore nesilected relations existing between those families, will be 

 sufficient to indicate the position of Amphizoa. 



A large series of penramerous, carniverous Coleoptera, may be characterized 

 as having the antenna? neither clavate nor lamellate, but usually filiform, and 

 the prothorax with distinct epimera and episterna ; the anterior coxce small, not 

 prominent, usually globular ; the trochanters always simple ; the anterior seg- 

 ments of the abdomen connate. This series may be divided into two great groups. 



I. In the first the anterior coxae are contained in the prosternum alone ; the 

 posterior coxe do not extend to the margin of the body, so that the first ventral 

 segment of the abdomen reaches the parapleural, and articulates with them. 

 (The antennae are always regular, the basal joints glabrous, the outer ones 

 pubescent; the anterior coxae always globular.) This group consists of the 

 Cicindelidae and Carabidae. 



II. In the second, the anterior coxae are received between the pro and mesos- 

 ternum, the posterior portion of the acetabulum being composed of the latter; 

 the posterior coxae extend to the margin of the body, so that the connection 

 between the parapleurae and first ventral segment of the abdomen is entirely 

 cut off. 'I'his group u composed of the aquatic families Haliplidae, Dytiscidae, 

 and Gyrinidae. 



Recurring now to the second group, it will be found that Amphizoa agrees 

 with it in the glabrous antennae, and in the form of the head, labrum, maxillae 

 and m^ntum ; the latter is large, deeply emarginate, with the lateral lobes 

 rounded; in the middle of the emargination is a broad, short, blunt tooth. The 

 ligula is large, filling the emargination of the chin, truncate at tip, and promi- 

 nent along the middle and appx, so as to present a form like the letter T. The 

 maxillae are of the ordinary form seen in Carabidae, but the inner lobe is not 

 ciliated. The prosternum is not elevated, it is not lobed in front, but poste- 

 riorly is produced in an obtuse spatula-like process, fitting into the mesoster- 

 num. which is excavated through its entire length; the anterior coxae are mode- 

 rately distant, small and round. The episterna are divided by an oblique suture 

 from the humerus to the middle coxae. The parapleurae are slightly triangular, 

 not appendiculate, and entirely separated from the ventral portion of the abdo- 

 men by the posterior coxre, which are transverse, flat externally, slightly 

 elevated and diverging at the insertion of the leg, as in Carabidae ; the diverg- 

 ing lobes are obtusely rounded, but not so much elevated as to allow the freedom 

 of motion observed in Dytiscidae. The legs are not at all compressed ; the femora 

 and tibiae are slender and finely scabrous, with elevated points, the terminal 

 spurs of the tibiae are small ; the tarsi are three-fourths as long as the tibiae, 

 filiform, glabrous, scarcely rouih or pubescent beneath; the first four joints are 

 equal, the last joint is equal to the three preceding united ; the claws are mode- 

 rate, equal and simple. 



It will be found in comparing these characters with those of Dytiscus, that 

 the only important differences are in the form of the feet, and in the smaller 

 size of the posterior coxae. Now, although the Dytiscidae and Haliplidae, which 

 are certainly closely related, agree in having natatorial feet, they differ greatly 

 in the modification of form, those of Haliplus being much nearer the terrestrial, 



