IIEMIPTERA. 563 



nutritive fluid, successively compressed, is forced up the main canal, and arrives at the oeso- 

 phagus ; the sheath of the sucker is often elbowed, or forms an angle. Like other sucking 

 insects, the Hemiptera possess salivary vessels. 



In the majority of the insects of this order the wing-covers are coriaceous, or crustaceous, 

 with the posterior extremity membranous, and forming, as it were, a kind of supplemental 

 piece ; they nearly always cross each other : those of other Hemiptera are merely thicker and 

 larger than the hind mngs, semi-membranous, like the wing-covers of the Orthoptera, and 

 sometimes opaque and coloured, sometimes transparent and veined. The wings have several 

 longitudinal folds. 



The composition of the thorax begins to exhibit the modifications which we meet with in 

 the following orders. Its anterior segment, hitherto known under the name of corselet 

 [thorax, or more strictly, prothorax], is in many of much less extent, and is incorporated with 

 the second, which is equally exposed. 



Many possess ocelli, but their number is generally only two. 



The Hemiptera [hke the Orthoptera] exhibit to us, in their three states, the same forms 

 and habits. The only change they undergo consists in the developement of wings, and an 

 increase in the size of the body. 



I divide the order into two sections \Heteroptera and Homoptera, regarded as distinct 

 orders by many English authors, under the names of Hemiptera and Homoptera]. 



In the first section, Heteroptera, the rostrum arises from the front of the head, the wing- 

 cases are membranous at the extremity, and the first segment of the thorax is nuich longer 

 than the others, and forms by itself the corselet. 



The wing-covers and wings are always horizontal, or slightly inchned. 



This section is composed of two families [Geocorisa and HydrocoriscB']. The first, 



Geocoris.'E (or Land-bugs), — 

 Have the antennae exposed, longer than the head, and inserted between the eyes, near their inner 

 margin ; the tarsi have [generally] three joints, the first of which is often very short. They form 

 tne genus 



CiMEX, Linn., — 

 Some of which, Longilabres, have the sheath of the sucker composed of four distinct and exposed 

 joints ; the upper hp is considerably prolonged beyond the head, like an awl, and transversely striated 

 on the upper side ; the tarsi have always three distinct joints, the first equal in length to, or longer 

 than the second. These species emit, in general, a very disagreeable scent, and suck other insects. 

 Sometimes the antennae, always fiUform, are composed of five joints ; the body is generally short, oval, 

 or rounded. 



ScuTELLERA, Lam.,— 



In which the scutellum covers the abdomen. Cimex lineatus, Linn, [a reputed British insect]. 



Pentatoma, Oliv., in which the scutellum covers only a portion of the upper-side of the abdomen. This genu?, 



as proposed by Olivier, comprises five others in the fii/stema Rhyngotorum of Fabricius ; but his 



groups are imperfectly characterized and badly arrang-ed. His genera ^lia and Ualys are Pen- 



tatomae, which have the head more prolonared, and advanced in front like a snout, more or less 



triangular. The tj^pe of the former is ^Elia acuminata [a rare British species], which differs 



from the rest in having the antennae covered at the base by the anterior and detached margin 



of the under-side of the thorax, and by the scutellum of much larger size, whereby this species 



more nearly approaches Scutellera. His genus Cydnus has the head seen from above, broad, 



semicircular ; the thorax transversely square, scarcely narrower in front than behind, and the 



tibiae are often spinose. These species are found on the ground ; some other species may also 



be united, which have the sternum neither keeled nor spined : such are Cimex ornatus and 



oloraceus, [handsome rare British species, forming Hahn's genus Eurydema], 



Other Pentatomse, having the mesosternum elevated in the manner of a keel, or exhibiting a point like a spine, 



are generically distinguished under the name of Edessa, employed by Fabricius. Many of the species which he 



introduces into this genus possess this character, which is also found in some of his species of Cimex, as P. h<e- 



morrhoidalls, Linn, [the type of Curtis's genus Acanthosoma, and P. griseus, the type of Laporte's genus 



Raphigaster"]. 



o o 2 



