j i iRTHOPTERA 



The proiwtum is large and frequently covers the head entirely; it is most varied in shape and ma) 

 be orbicular, semi-orbicular, cucullate, with reflected border, rugose or tuberculate. The presternum is 



small and inconspicuous. 



The mesonotum and metaiwtum are very simular to one another in structure; in some genera a small 

 triangular part of the mesonotum, the scutellum, is exposed when the tegmina and wings are closed. 

 The meso- and metasternum though larger than the presternum are not readily to be seen in dried 

 specimens. 



The tegmina or elytra may be completely developed, abbreviated, scale-like or absent; in many 

 genera the males are winged, but the females are apterous (Polyphaga, Doopcltis etc.). 



The tegmina overlap to a greater or less extent; they are horny, coriaceous or membranous; in 

 the genus Diaphana they arc entirely membranous and transparent, in the genus Holocompsa the basal 

 half is coriaceous and opaque, the apical half membranous and transparent, producing the appearance of 

 the tegmen of a Heteropterous bug'. Occasionally the tegmina are ciliated {Polyphaga, Corydta) or covered 

 with a sericeous pile (Nyctibora, Paratropes). Pour main nervures or veins issuing from the base of the 

 tegmen may be distinguished, viz : i. The mediastinal vein, which runs to the anterior border of the 

 tegmen before its middle; the part of the tegmen between its anterior border and the mediastinal vein 

 is known as the mediastinal area; blanches or secondary veins are emitted by the mediastinal vein only 

 towards the anterior border. 2. The radial vein extends to the apex oi the tegmen dividing it into two 

 more or less unequal parts, the marginal area and the discoidal area; in some genera the marginal area 

 is almost equal in breadth to the discoidal area, in others it is a narrow strip; branches are given off to 

 the anterior margin of the tegmen (costal veins) and sometimes to the apex. 3. The ulnar or median 

 vein gives off a number of branches to the apex and to the sutural margin ol the tegmen, when these 

 branches unite in two main trunks they are termed the anterior ulnar or interno-median and the posterior 

 ulnar or externo-median. 4. The anal vein inns in a curved line to the sutural margin at a point before 

 its middle; it is usually well-marked and sometimes impressed; the part of the tegmen enclosed bv it is 

 tin- anal area, and is occupied bv a series of more or less parallel secondary veins, known as the axillary 

 veins, whose number ranges from three to twelve or more. These four main nervures arc generally 

 distinct, but in tegmina of corneous texture they tend to disappear ; the secondary veins more frequently 

 become obliterated. 



The wings in some genera are reduced or absent, even when the tegmina are well-developed 

 {Phlebonotus, Phenacisma), but reduction of the tegmina is always accompanied by reduction ol the w ings. 

 Tire general form of the expanded wing is a triangle, the apex of the triangle being attached to the 

 metanotum ; an anterior part and a posterior part can be distinguished, the anal or dividing vein ma iking 

 the division of the two parts. The veins of the tegmina have their counterpart in the wing; the ulnar 

 vein nearly always is composed of two distinct branches, the anterior ulnar, which is usually unbranched, 

 and the posterior ulnar, which gives off numerous branches towards the dividing vein and apex of the 

 wing ; the dividing vein is unbranched. The posterior part ol the w ing corresponds to the anal area 1 A the 

 tegmen and is traversed by several radiating axillary veins, which act like the ribs of a fan and on w Inch 

 this part of the wing can fold up, the folded up portion then doubling under the anterior part of the wing. 

 In the Corydinse the anal area however does not fold up like a fan, but merely doubles under the antei ii u 

 part of the wing. A small part of the wing known as the triangular apical area occurs in some genera 

 (e. g. Ectobia, Chorisoncara, Oxyhaloa 1; in these, when the wing is folded, this triangular area is left at the tip 

 of the wing unin eluded in the main told, but it is doubled over or rolled up and lies on the anterior part of 

 the wing, it also folds on itself along a longitudinal crease; when the wing is expanded this area unfolds and 

 is seen to lie between the dividing vein and the posterior ulnar vein, which are often somewhat distorted 

 to accomodate it. In the genera Anaphcia and Plectoptera the apical area is large and often equals the rest 



