FAM. MEMBRACID.E 19 



is absent ; but tliis judgment is based on the study of Heteroptera only, and the Membracidee are 

 apparently representative of a different type of notal structure. In the more distinct forms this 

 pseudonotum or postnotum is connected to the scutelluin by one or more chitinized bridges, breaking 

 the connecting membrane up into a series of lacunte. In two subfamilies, the Membyaciita and the 

 Damiiia:. an indication of a postphragma is found. This appears as ;in extra fold of the mesonotum, 

 posterior to the pseudonotum, membranous and irregular but of considerable size and fairly constant. 

 Only one wing process is found, this being the posterior. The anterior process is barely indicated in 

 a few forms by a thickening or doubling of the lateral margin of the scutum at its extreme ventro- 

 caudal angle. 



The pleuron of the mesothorax is more or less turned under the lateral margin of the notum, 

 forming part of the ventral body wall. The episternum is a single irregular sclerite, closely fused with 

 the lateral notum in the mature insect but separated by the anteriorly extended wing cavity in the 

 nymph. The distal (ventral) extremity is produced into the sternal region. The caudo-ventral margin 

 forms the upper edge of the mesocoxal cavity. In certain forms of the subf. Membracina the 

 episternum seems to be divided by a transverse suture across its lower third. In this subfamily, also, 

 the entire episternum is elevated so that it forms part of the articulatory surface of the wing. in the 

 other subfamilies the episternum is crowded downward, and the produced notum serves as both the 

 dorsal and the ventral margin of the wing cavity at its anterior end and only braces the wing at the 

 posterior extremit)' of this cavity. Just cephalad of the episternum is a well-developed spiracle situated 

 in the intersegmental membrane. 



The epimeron consists of two distinct sclerites. The larger is roughly subquadrangular and joins 

 the notum cephalo-dorsad and the episternum cephalo-ventrad. The second is a small triangular 

 piece attached to the dorso-caudal margin of the first and no doubt originating as part of that sclerite. 

 In the nymphal exoskeleton the suture between these two sclerites is indicated but not pronounced. 

 The dorsal margins of the two epimeral sclerites form the larger part of the lower margin of the wing 

 cavity, while the ventral margin of the anterior sclerite forms part of the dorsal-caudal boundary of the 

 coxal cavity. In general it would appear that both the pleural sclerites of the Membracida tend toward 

 subdivision. This would agree with the « anepimeron and katepimeron » and the « anepisternum and 

 katepisternum » of Crampton (igog), but the homologies are not clear if that author's terminology limits 

 the division to « upper » and k lower » regions. No paraptera of any description have been found. 

 A much-wrinkled connecting membrane at the anterior base of the wing may represent an episternal 

 parapterum or preparapterum, but there seems to be no indication of epimeral paraptera or postpa- 

 raptera. The basal wing membranes are not thickened and certainly not chitinized. Directly ventrad of 

 the episternum is a small but well-defined trochantin. This sclerite is roughly triangular in shape, with 

 the base against the episternum and the apex extending cephalo-ventrad to form part of the ventral 

 margin of the coxal cavity. 



The sternum of the mesothorax indicates by its sculpture a development from three distinct 

 sclerites, but even in the nymphal forms these sclerites are not clearly distinguished. For the sake 

 of convenience in description, the areas may be given the usual terms of presternum, sternum and 

 sternellum, although it is not at all certain that the regions so designated are strictly homologous with 

 the same sclerites in other insects. The entire sternum is roughly shield-shaped and in the mature 

 insect shows an anterior fold, a central plate, and a rather distinct posterior piece consisting of a thin 

 arm partly encircling the coxal cavity on each side of a lobcd central extension. The presternum is 

 very indistinctly set off from the sternum, and indeed in very few cases can the faint lateral hnes that 

 are believed to represent sutures be determined. The sclerite can be distinguished, however, by the 

 ventral lobe which is produced downward just behind the presteinum. The central sternuin is a flat, 



