REVISION OF STREPSIPTEBA — PIERCE. 65 



analogous to the metasternal groove found in Heteroptera, which 

 Stal, in the "Enumeratio Hemipterorum," in his classification of the 

 Pentatomidae, calls the "sulcus;" which Uhler, 1878, in his "Summary 

 of the Cydnidae of North America," calls the "ostiolar canal;" 

 winch Signoret, 1883, in his "Group ties Cydnides," calls the "canal 

 ostiolaire;" and which Schouteden, in the "Genera Insectorum," 

 speaks of as the "orifice" in the Pentatomidae. This organ may be 

 known as the mesostigmatal lobe. (See pi. 6, fig. 4.) 



Wlnle observing the activities of a male Acroschismus pallidus 

 the writer noted that the characteristic buzz continued as long as 

 the elytra were in motion and ceased when they became quiet. 

 At the ventral base of the elytra is a hook-like projection which is 

 very close to the mesostigmatal lobe. Whether this lobe and hook 

 play some part in the noise-making is of course merely conjectural, 

 but perhaps possible. 



The metathorax is much more complex and occupies nearly one 

 half of the length of the body. On the dorsal median line may be 

 differentiated four distinct parts. The basal piece is subtriangular 

 or keystone shaped. It is the prsescutum of Audouin and West- 

 wood, and known to Kirby and Saunders as the "scutellum." The 

 second piece is similar in shape but reversed so that the two form a 

 sort of spindle. Tins is the scutellum of Westwood, known to Au- 

 douin as the "scutum," and to Kirby and Saunders as the "inter- 

 lumbium." The third piece is oblique or vertical, transverse, and 

 corneous or membranaceous. It is the postlumbium of Kirby, 

 Westwood, and Saunders, and the "scutellum" of Audouin. The 

 apical piece is produced conical, convex, covering the base of the 

 abdomen and beneath concave. It is postscutellum of Audouin and 

 Westwood, and the "proscutellum" of Kirby and Saunders. Very 

 unfortunately the writer did not translate the explanation of Nasso- 

 now's plate (Nassonow, 1892 c, pi. 2) dealing with these structures, 

 otherwise these parts might be named more correctly. At the sides 

 of praescutum and scutellum are the lumbi which together form the 

 scutum. These were known to Audouin as "epimera." Behind 

 the lumbi and at the side of the postscutellum are the femoralia. 

 Kirby and Saunders have distinguished below the lumbi a longi- 

 tudinal, sublanceolate piece, the pleura; a second parallel piece to 

 the base of winch the wing is attached, the parapleura; this piece lying 

 between the base of the wing and a small piece known as the scapula. 

 The metasternum is also variously divided, but no particular names 

 have been given the parts. (See pi. 6, figs. 6, 7.) 



The wing venation is simple, radial. The wings folded longi- 

 tudinally only. A node is sometimes present on the costal margin, 

 as, for instance, Apractelytra schwarzi. The most generalized wrings 



