350 PROCEEDINGS OF THE NATIONAL MUSEUM vol. in 



it appears dulled due to the presence of numerous minute, inter- 

 secting cracks and wrinkles like those on the surface of human skin. 



Family Cydnidae 



Cydnides BiUberg, 1820, p. 70. 



Size small to large, 1.6-16.1, oblong to oval, dorsum subdepressed 

 to strongly convex, venter strongly convex. 



Head : Quadrate to semicircular, more or less widened or explanate 

 laterally; antennae 4- or 5-segmented, inserted ventrally on head 

 near ventral angle of eye; ventral surface of eye attaining posterior 

 margin of head; labium 4-segmented, inserted near or beneath apex 

 of clypeus, surpassing base of head, sometimes reaching well onto 

 abdomen. 



Thorax: Pronotum large, concealing mesonotum and metanotum 

 except for the usually very large, triangular or subtriangular scutellum ; 

 clavus and corium opaque, latter subtriangular, broadened at apex, 

 frenum reaching beyond middle of scutellum; membrane with veins 

 usually weak, simple or anastomosing; legs more or less strongly 

 spined on tibiae, especially anterior pair which are more or less 

 flattened and have single row of very stout, blunt spines on lateral 

 margin (except in Scaptocorinae) ; middle and posterior coxae with 

 apical fringe of close-set bristles (fig. 114); tarsus 3-segmented (absent 

 from posterior legs of Scaptocoris). For additional discussion of 

 family definition within the Pentatomoidea see the introduction. 



Biological information concerning the Cydnidae is scattered and 

 mostly fragmentary. But from what has been published there may 

 be deduced a rather incomplete outline of the life cj^cle. Biologically 

 the Cydnidae may be considered in two groups. One group consists 

 of species like those of Sehirus (not necessarily all Seliirinae) in which 

 both the nymphal and adult stages feed on parts of plants that grow 

 above ground; in so doing they closely resemble the activities of the 

 great percentage of the Pentatomoidea. The second type, which is 

 apparently characteristic of species of all cydnid genera except 

 Sehirus, involves nymphal and adult feeding on roots and possibly 

 other underground parts of plants. This habit of underground 

 feeding has suggested for the family the popular name of "burrower 

 bugs." 



Although no life history of an American cydnid has appeared in 

 literature, the activities of Sehirus cinctus (Beauvois) probably can 

 be predicted somewhat from results published on certain European 

 members of the genus. Southwood (1949) and Southwood and Hine 

 (1950) have given a rather full account of Sehirus bicolor (Linnaeus) 



