7o8 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [BuU. 



Family LYGAEIDAE. 

 By Harry Gardner Barber, A.M. 



Preliminary to the publication of this paper synoptic keys were 

 prepared for distinguishing the subfamilies and genera of Lygaei- 

 dae known to occur within the limits of the United States. These 

 were published in Psyche, Vol. xxiv, pp. 128-135, 1917, and Vol. 

 XXV, pp. 71-88, 1918. These keys have here been revised to suit 

 the purposes of this paper. 



Stal's various synopses of this family form a reliable foundation 

 for any treatment of the subdivisions. Later writers, myself 

 included, have been able to offer little in the way of change or 

 improvement of his system. Major diagnostic characters used by 

 Stal and having an important bearing, are the position of the spira- 

 cles, whether dorsal or ventral, and the character of the suture 

 between the second and third ventral abdominal segments. This 

 suture in most of the subfamilies is straight and reaches the 

 lateral margins of the abdomen, but in the largest subfamily — 

 Rhyparochrominae — it is outwardly curved forward and does not 

 reach the margin of the body, except in the genus Plinthisus. 



Other important subfamily characters may be mentioned. The 

 tylus or median lobe of the head may sometimes be sulcate or 

 grooved (Geocorinae). The bucculae, elevated ridges or plates 

 on either side of the base of the rostrum, are reduced or some- 

 times extended to the base of head (Oxycareninae). The fore 

 femora may be more or less enlarged and are often provided with 

 teeth or spines beneath as in most of the Rhyparochrominae. The 

 hemelytra consist of three parts : the clavus, a relatively narrow 

 strip along the sides of the scutellum, the corium being the 

 remainder of the coriaceous part and the terminal membrane. The 

 clavus, most frequently parallel-sided, may become narrowed, 

 apically (Geocorinae) or widened (Cyminae in part). The line of 

 meeting of the two clavi behind the apex of the scutellum is known 

 as the commissure and its length is distinctive in the two fore- 

 mentioned families. The relative expansion of the corium as well 

 as its lack of punctation may play some important part. 



It is not necessary to mention all of the characters used for 

 tribal and generic diagnostic purposes. However, one or two 

 points may be discussed to advantage. The antenniferous tuber- 

 cles are the more or less triangular lateral processes forming the 

 sides of the head, upon which the four-segmented antennae are 

 mounted. These may be apically truncated or externally acute 

 and viewed from the side are either straight or more or less 

 inclined. The distance between the apex of this tubercle and the 

 anterior margin of the eye, relative to the space back of the eye 

 (post-ocular space) may be of great significance especially in the 

 Rhyparochrominae. The character of the odoriferus orifices 

 (openings of the scent glands) usually placed on the metapleura 



