22 Mr. H. W. Bates on the 



inevitable, and the more attentively the Longicorns are studied 

 the more hopeless rigid definitions of genera and subfamilies 

 appear. 



The RMnotragince are a subfamily of the same section of 

 the Cerambycidge to which the familiar genera CaUicJtroma, 

 NecT/dalis, &c. belong, «. e. having finely faceted eyes. They 

 are remarkable for the very general abbreviation of the elytra 

 in the species, and the mimetic resemblances that many of them 

 bear to wasps, bees, Ichneumonida^, and so forth — aresemblance 

 which is much aided by the subrudimentary condition of the 

 elytra and the prevailing style of coloration. In the imago 

 state they frequent flowers, in company with the Hymenoptera 

 many of them resemble, and are very nimble fliers, probably 

 in consequence of the abbreviation of the elytra and great 

 development of the membranous wings. An almost universal 

 character of the group is tlie large volume of the eyes, especially 

 of the lower lobes, wliicli in the males nearly meet in front : 

 this forms the nearest approach to an exclusive character of 

 the group ; but it disappears in some few species. The head, 

 too, is very generally elongated below the eyes, forming a 

 muzzle ; but this character exists in several other subfamilies 

 of Cerambycida3. The palpi are short, and their terminal joints 

 nearly cylindrical or cylindric-ovate, truncated at the apex. 

 The antenna3 are almost always more or less serrated from the 

 sixth joint ; and the third to sixth joints are furnished with 

 setae on their outer sides. The thorax is cylindrical or ovate, 

 always unarmed at the sides. The prosternum forms a distinct, 

 though narrow, level plate between the anterior coxaj ; and the 

 episterna of the metasternum are always triangular and very 

 broad in front. The anterior coxaj are generally obliquely ex- 

 serted ; but this is an inconstant character. 



In deciding whether a Cerambycid with finely faceted eyes 

 belongs to this group or not, the characters chiefly to be looked 

 to are (1) the volume of the lower lobe of the eyes and the 

 extent to which this has become frontal, (2) the presence of a 

 distinct prosternal process, and (3) the prolongation of the head 

 below the eyes. Species in which the eyes are lateral and the 

 prosternal process narrow or obsolete are either Necydalinoi or 

 Molorchince. The abbreviation of the elytra is not an essential 

 character. The ti-iangular shape of the metasternal episterna 

 ought, however, I think, to be considered a sine qua non ; this 

 would exclude Trichomesia^ an Australian genus which La- 

 cordaire places in the "groupe,"and wliich is the only form in 

 it not belonging to Tropical America. 



Although so forbidding to the pm-e systematist, the Rhino- 

 tragince are full of interest to the general naturalist, on accoimt 



