HEMIPTERA. 567 



JV. glauca, Linn., more than half an inch long, [is one of our commonest water insects]: it swims upon its back in 

 01 der the better to seize its prey, and is able to prick sharply. 



Plea, Leach, is founded upon Notonecta minutissima, Linn., which has the ungues of the hind feet large, and 

 tl:e elytra entirely crustaceous- 



The second section of the Hemiptera, that of the 



HoMOPTERA, Latr., — 

 Is distinguished from the preceding by the following characters : — The proboscis arises from the 

 lowest part of the head, near the breast, or even, as it appears, between the two fore-feet. 

 The wing-covers (nearly always roof-hke) are throughout of the same consistence and semi- 

 membranous, sometimes even nearly like the wings. The three segments of the thorax are 

 united into a mass, and the first is often shorter than the following. All the Hemiptera of 

 this section feed only upon the fluids of vegetables ; the females have a scaly ovipositor, gene- 

 rally composed of three denticulated plates, and lodged in a scabbard of two valves : they use 

 this instrument as a saw to make notches in vegetables, in order to deposit then" eggs. The ter- 

 minal insects of this section undergo a kind of complete metamorphosis. 

 I divide it into three families, \_Cicadarice, Aphidii, and GalUnsecta.'] 



THE FIRST FAMILY OF THE HOMOPTEROUS HEMIPTERA,— 

 The Cicadari.e, — 

 Comprises those which have three joints in the tarsi, and the antennae generally very small, coHic, or 

 awl-shaped, from 3- to 6-jointed, including a very slender seta, with which they are terminated. The 

 females are provided with a denticulated, saw-hke ovipositor. Messrs. Ramdohr, Marcel de Serres, 

 Leon Dufour, and Strauss, have studied the anatomy of different insects of this family with great care; 

 the latter has not yet however published his researches. Amongst the others, M. Leon Dufour is the 

 author whose investigations are the most extended and complete, at least as regards the digestive and 

 generative systems, as is easily proved on referring to his memoir intitled Recherches anatomiques sur 

 les Cigales, inserted in the fifth volume of the Annates des Sciences naturelles. 



Some of the Cicadarise are named Chanteuses, and have the antennae composed of six joints and three 

 oceUi. The mesothorax, seen from above, is much more spacious than the prothorax, and is narrowed 

 towards its extremity, where it forms a kind of scutellum. It is nearly of the same form in the Fol- 

 gorae and other genera separated therefrom. The mesothorax is often of a reversed triangular form, 

 and the prothorax is generally very short and transverse. In Membracis, Cicadella, &c., it is, on the 

 contrary, much more extensive than the other thoracic segments, and very much developed in one or 

 the other direction, and the mesothorax appears only in the form of an ordinary triangular scutellum. 

 In the whole of the family, the mesothorax is very short and concealed. Considered in respect to other 

 insects, the head of the Cicadariae, seen in front, exhibits immediately above the labrum a triangular 

 space, answering to the epistome or clypeus, above which is another space, often swollen and striated ; 

 above this is the forehead, and which is succeeded by the vertex or superior part of the head. 



The Chanteuses comprise the Cicadte manniferfe, Linn., or the genus Tettigonia, Fabr., and form 



with me the genus 



Cicada, Oliv. (Tettigonia, Fabr.). 

 These insects, in which the ■wing-covers are almost always transparent and veined, differ from the followin"- not 

 only in the structure of their antennae, and the number of the ocelli, but also in not possessing the power of 

 leaping ; the males also produce in the hottest part of the day a kind of monotonous and noisy music, whence they 

 have been termed by authors "chanteuses," or singers. The organs of sound are placed at each side of the base 

 of the abdomen, internal, and covered by a cartilaginous plate like a shutter, and which is an appendage of the 

 under side of the metathorax. The cavity which incloses these instruments is divided into two partitions by a 

 scaly and triangular edge ; seen from the under side of the body, each cell exhibits anteriorly a white and folded 

 membrane, and in the hollow part, a stretched-out slender membrane, which Reaumur calls the mirror : if this 

 part of the body be opened from above on each side, there is seen another folded membrane, which is moved by a 

 very powerful muscle, composed of a great number of straight and parallel fibres extending from the scaly rido-e- 

 this membrane is the timbale. The muscles, by contracting and relaxing with quickness, act upon the timbales, 

 stretching tlieni out, or bringing them into their natural state, whereby the sounds are produced, and which, even 

 after tlie death of the animal, may be repeated by moving the parts over each other in the manner they act whilst 

 alive. 



