582 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 57. 



{posty is subtriangular; in forms as Enoclerus, large with a small 

 chitinous median plate and a deep ventral notch which inside de- 

 velops into a strong spina ; in other forms as Maiioj^hylla, rather in- 

 significant. 



The Meso- and Metathorax {Ms and Mt) are subequal. 



Notches {Nodi). — The notches belonging to meso- and meta- 

 thorax are present in the same numbers and placed in the same way 

 as between pro- and meso-thorax. Between metathorax and first 

 abdominal segment the dorsal notch is pushed somewhat downwards, 

 while the lateral notch occurs on the same horizontal level as the 

 preceding lateral notch ; the ventral notch is only indicated faintly, 

 is without spina, and confluent with the sternal notch just in front 

 of it ; the pleural and sternal notches as in prothorax. 



Sutures. — The dorso-lateral suture, separating tergum and epi- 

 pleurum is indistinct ; the ventro-lateral suture below epipleurum and 

 between two succeeding lateral notches is horizontal and straight; 

 it is shallow or even indistinct between the lateral notch in front 

 of the segment and the pleural notch immediately behind, but dis- 

 tinct between this pleural notch and the lateral notch behind; it is 

 especially deep above the prehypopleural chitinization ; the scuto- 

 scutellar suture, which separates the scutal and scutellar areas, 

 is short and transversal. 



Areas. — ^Tergum is subsellate with a short, straight, transversal 

 front margin above the dorsal notch in front of a segment, with a 

 deeply curvate, posteriorly oblique side margin between two subse- 

 quent dorsal notches and with a short hind margin above the dorsal 

 notch behind. The tergal areas are slightly indicated. Prescutum 

 ipse) is bandlike and mainly developed as a dorsal part of an inter- 

 segmental membrane.2 Scutum {sc) and Scutellum {scl) are only 

 distinctly separated in front and behind the scuto-scutellar suture. 

 Just behind and below this suture a chitinous plate is developed in 

 many genera ; usually larger on meso- than on metathorax. The Alar 

 area {aa) is large and reaches the ventro-lateral suture in front of 

 the pleural notch after having replaced or possibly incorporated the 



1 The term Poststernellum is here applied to that area behind sternellum which is 

 limited anteriorly by the transverse, straight suture through a sternal notch between 

 two corresponding lateral notches, and posteriorly by the transverse, curved or medianly 

 angular suture tlirough the ventral notch right behind the sternal notch and between the 

 same pair of lateral notches. 



2 The intersegmental membrane is not a constant, well-defined morphological forma- 

 tion, but is a structure developed for purely mechanical purposes and of changing 

 morphological nature in different coleopterous families as well as in the different insect 

 orders ; sometimes the membrane is to be derived from the anterior, sometimes from the 

 posterior parts of the two segments which it connects. The attachments of the longi- 

 tudinal segmental muscles indicate the morphological nature of the membrane ; if they 

 attach in front of the membrane this is composed of presegmental elements, if they 

 attach behind the membrane this is of postsegmental nature. In the Clerids the dorsal 

 part of the intersegmental membrane belongs to prescutum, the lateral part contains both 

 pre- and post-epipleural elements, and the ventral part below the lateral notch belongs 

 to poststernellum. 



