DESCRIPTION OF PARTS. 9 



quently dentate or toothed, the teeth being arranged so as to shut within each other. Below 

 the upper jaw are the feeler jaws, or maxilla 1 : these also move horizontally : they are 

 smaller, and, instead of notches, their inner edges are furnished with bristles or hairs ; they 

 are articulated to the throat by a hinge (cdrdo), which places them at right angles to the 

 stipe or stalk, which last is pretty thick and strong at its upper part. Attached to this is 

 the feeler-bearer, so called because the maxillary palpus is inserted on it* outer edge. The 

 terminal portion of the maxilla is the maxillary lobe, which is frequently toothed at its 

 extremity. The maxillary palpus is a filiform, jointed process, which always distinguishes 

 the maxilla? from the mandibles. The proportion of joints is variable, and in number they 

 never exceed six.. The terminal joint is quite variable in form in the different genera, and 

 hence becomes an important characteristic. The under lip is called a labium; it antagonizes 

 the labruni ; at its base is the mentum or chin. The anterior part bears the labial palpi : 

 the terminal portion is the ligtda, and is often lobed. The labial palpi are jointed, but the 

 joints never exceed four. The tongue, in the Carabidae, is a lining membrane of the under 

 lip, which protrudes along its anterior angles, or in front : it is obscure among the Coleo- 

 ptera, but more distinct among the Orthoptera. The mouth designed for suction is not very 

 dissimilar to the one formed for mastication. The mandibles have undergone modifications 

 which are referred to three types, that have received the following appellations : prcmuscis, 

 proboscis, and haustellum. The tube is formed by the elongation of the maxilla and accessory 

 parts : so also it is formed by the mandibles. 



The thorax is the section of the insect which lies between the head and abdomen : it 

 supports the legs. Three principal pieces enter into its composition : the anterior supports 

 the fore-legs, and is called the prothorax ; the next, the mesothorax, which supports the 

 middle legs and fore-wings ; the last, the metathorax, which supports the hind-legs and 

 hind-wings. The inferior part of the thorax is covered by a plate, called the prosfcrnum by 

 Burmeister. The scutellum is a triangular piece of integument interposed between the 

 elytra at their base : sometimes it is concealed by the elytra. Connected with the scutellum 

 is the frenum, a membrane designed to regulate the quantity of movement belonging to the 

 elytra : in the Fulgura it consists of cartilaginous elastic rings, which admit of tension and 

 relaxation. The mesothorax has another important division, called the scapula : they assist 

 in forming the articulating socket of the elytra ; they pass down the sides of the second 

 thoracic segment. The mesothorax has also its spiracle : on the under side of this segment 

 is placed the mesosternum; it contains the sockets of the middle legs. The metathorax is 

 the posterior segment of the thorax, which supports the hind-legs and the inferior wings ; : 

 it is well developed in the Coleoptera and Orthoptera. The best authorities regard it as 

 admitting of a division into seven pieces : the dorsal portion is the metanotum ; it is 

 quadrangular, and notched in front. The metathorax is separated from the abdomen by a 

 parietal wall called the metaphragma, and from the mesothorax by the mescphragma. The 

 lateral portions of the metathorax are provided with horny plates, termed by Kiebv and 

 [Agricultural Report — Vol. v.] 2 



