62 
Psyche 
[April 
In naming the sclerites of the thorax the terminology used 
' by Young (1921), which is largely based on Crampton (1914), 
is employed. 
The dorsal aspect of the thorax is completely covered by 
the notum of the mesothorax, as defined by Snodgrass (1909a), 
or the mesonotum. This is divided by two transverse sutures 
into three sclerites, the prescutum (psc^), scutum (sc2) and 
scutellum (sh). The prescutum, including the humeral calli 
(he) is yellow in color, with four longitudinal bands of velvety- 
black. In the males the yellow coloration extends backward 
onto the scutum where it merges with the black of that sclerite. 
The scutellum of both sexes appears black to the naked eye, but 
under the binocular most specimens show a faint tinge of very 
dark orange. The scutum is produced laterally into an anterior 
wing process, the suralare (sur), and a posterior wing process, 
the adanale (ad). The scutellar bridge of Walton (sb) is seen as 
a lateral overlapping of the scutellum onto the scutum. Below 
this is the axillary cord (axe) of Snodgrass (1909a), which is 
produced to form the margin of the calypteres. A posttergite 
(pt2) is demarked behind the scutellum. The pseudonotum or 
postnotum of Snodgrass, which he would recommend calling 
the ‘^postscutellum’’, in this case is located ventrad of the scu- 
tellum, and cannot be seen from above. It is divided into a 
median plate, the meditergite (mt^), and two pairs of lateral 
plates, the anapleurotergites (aplt^) and the katapleurotergites 
(kplt2). Mention may logically be made here of the character 
recently reported by Malloch (1923) for differentiating muscoid 
flies. In Malloch’s own words, ‘Tt is invariably possible to 
distinguish between the Sarcophagidse, Muscidse and Calli- 
phoridaD on one hand, and the Tachinidse and Dexiidse on the 
other, by the shape of the metanotum. In the last two this is 
biconvex in profile, there being a small but distinct convexity 
just below the scutellum which is absent in the other three 
families known to me.’’ The use of the term “metanotum” by 
Malloch follows the usage of older taxonomic workers, and is 
morphologically inaccurate. It is really the meditergite (mt^) 
of the postscutellum which is meant, and the “biconvexity” 
