429 



(mscl). There is a deep invagination near its cephalic angle but no 

 invaginations of the internal skeleton occur here. Caudad of the 

 caudal extremity of the dorsal carina and adjacent to the wing bases 

 there are two small, frequently subcrescentic pieces which are approxi- 

 mate on the mesal margins and extend well towards the first lateral 

 suture of the thorax. These are the combined mesepisternal paraptera 

 (p). Caudad of the mesepisternal paraptera, but on a distinctly lower 

 level and between the first pair of wings, is the second portion of the 

 mesonotum, which consists of a number of irregular hummocks sep- 

 arated by depressions, sutures, and ridges. Just caudad of the parap- 

 tera on the dorso-meson there is a very deep invagination of the mesa- 

 phragma, which is situated near the cephalic margin of the mesoscutum. 

 (msec). At this point the mesoscutum is narrow, but widens soon 

 after extending caudad a short distance and forms a process, the 

 anterior wing-process. From this point the margin extends caudad 

 and forms a similar process, the posterior wing-process. The caudal 

 boundarv of the scutum is formed by a heavy chitinous line, bent 

 caudad and extending from side to side between the caudal wing- 

 processes. ' From the caudal wing-processes the lateral margins of the 

 mesonotum, now the scutellum, extend caudad to the point of entrance 

 of the spring-vein (Figs. 46, 47; spn) which always marks the caudal 

 iiiargin of this sclerite. The central portion of the scutellum is ele- 

 vated to form a sort of knob, which is heavily chitinized. The portions 

 on either side of this are depressed and as a rule less heavily chitinized 

 than the elevated portion. The area caudad of the spring-vein is the 

 postscutellum (mopl), the latter extending as far as the deep fold 

 v^'hich forms the cephalic border of the metaprescutum. 



Mctanotuui (Figs. 46, 47). — The metaprescutum (psct) is a nar- 

 row, transverse, heavily chitinized sclerite forming the cephalic mar- 

 gin of the metanotum. It is in great part covered by the membranous 

 postscutellum of the mesonotum but can usually be seen through the 

 latter. On the lateral angles, there are slight ental projections. Caudad 

 of the transverse prescutum, there are four large areas composing 

 the scutum (mtsc) and three deep longitudinal folds which mark ofif 

 the fou,r areas, but no primary sutures. There is also a somewhat 

 irregular area caudad of the four larger ones. The caudal margin of 

 the scutum is depressed laterad, and the latero-caudal angles project 

 and form the anterior wing-processes. The metascutellum (masl) 

 is similar to the mesoscutellum (mosl), the caudal boundary being 

 marked by a spring-vein (spn) and the sclerite, as in the former case, 

 having a raised central portion and depressed lateral ones. The postscu- 



