lO SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 56 



The prcBscutai crest. A narrow endoskeletal crest arises from the 

 dorsal side and projects inward. This cannot be considered as a 

 phragma. I name this the pr?escutal crest (pi. 2, fig. 4, /). It arises 

 from the boundary between the praescutum and the paratrema. 

 bridges the former, follows the ventral edge of the praescutum, and 

 ends at the boundary between the prrescutum and the scutum. Here 

 it is connected by ligamentous attachments with the parapterum (pi. 

 2, fig. 4, pn). 



The mesapodema (great entopleuron, Lowne ; pi. i, fig. 2; pi. 2, 

 fig. 4, a) arises at the ano-dorsal curvature of the mesosternum. It 

 does not wholly correspond to the apodema of Kolbe, but as it be- 

 longs almost entirely to the pleural portion of the thorax I will 

 retain the above designation. Farther on the mesapodema follows 

 the curvature of the mesosternum as far as the parapleurum to the 

 anal and ventral corner of which it is attached. From here it ex- 

 tends, in the shape of a crest, above the boundary between epimerum 

 and episternum (pi. 2, fig. 4; pi. 10, fig. 28, l-^) to the root of the 

 wing. I call this crest the episternal crest because it is attached to 

 a process of the episternum, the processus pteralis thoracis IV. The 

 episternal crest gradually passes into a tendinous ligament. The 

 mesapodema bends first towards the anus and so forms, with the 

 episternum, the episternal pouch, then it turns toward the head and 

 projects toward the interior as a strong, jagged protuberance, the 

 processus serratus (pi. i, fig. 2, a). 



The mesapophysis (pi. i, fig. 2, ap) consists properly of two 

 pieces, belonging to the two mesosternums. As already mentioned, 

 the two mesosternums are joined to a single plate which projects 

 vertically upwards into the interior (pi. i, fig. 2, ap). This plate 

 narrows distally, and finally again divides into two stalk-like pieces. 

 These stalks diverge from each other and bear at their ends twisted 

 cup-like enlargements, the processus alveolati (pi. i, fig. 2, ap). 



In conclusion, there should be mentioned a peculiar skeletal struc- 

 ture, the so-called 



Parapterum (Audouin, Lowne; pi. 2, fig. 4, pn). This lies near 

 the parapleurum, and is not firmly attached to any portion of the 

 skeleton. It consists of a stalk-like part, the stem, which terminates 

 in an enlargement, the head. The anal portion of the head reaches 

 as far as the root of the wing, while the rostral portion, as already 

 mentioned, is united by a ligament to the end of the pra;scutal border. 

 The parapleurum serves, as do the above-mentioned endoskeletal 



