1920] Seamans: Anatomy of A nthomyia 207 



the praescutum, and three on the scutum. These are the 

 dorsocentral bristles, those on the praescutum being the anterior 

 dorsocentrals, and those on the scutum being the posterior 

 dorsocentrals. Between the rows of dorsocentral bristles are 

 two rows of setae, never very symmetrical, variable in number, 

 starting with two strong bristles on the praescutum and ending 

 in two strong bristles at the posterior end of the scutum. 

 These are the acrostichal bristles (acr). Two strong bristles 

 are present on the humeral callosities, which are known as the 

 humeral bristles (hb). (Figs. 9, 10 and 12). On each side of 

 the praescutum, close to the humeral callosities, is located a 

 strong bristle, the posthumeral bristle (phm.) Near the 

 posterior angle of the praescutum there is a strong bristle, the 

 praesutural bristle (prsl). On the sides of the praescutum^ 

 next to the notopleural suture there are two strong bristles, the 

 notopleural bristles (npl). (Fig. 12). 



In addition to the bristles mentioned above, the scutum 

 bears two bristles outside of each row of dorsocentral bristles, 

 the intra-alar bristles (ial). Below and somewhat anterior to- 

 the intra-alar bristles, on the sides of the scutum, are located 

 the supra-alar bristles (sal) . In some of the Anthomyidae there 

 are three supra-alar bristles, the anterior one being the "Pro"' 

 of Stein. Posterior to these and located on the side and dorsum 

 of the postalar callosities, are the post-alar bristles, (pal). 



The bristles of the scutellum are small except for one pair of 

 strong bristles located at the anterior angles of the scutellum,. 

 and a pair of still larger ones, located on the posterior border of 

 the apex. This last pair have been called the apical bristles or 

 scutellar apicals (scla). 



The prothorax is indistinct when viewed from the side, 

 being represented by three visible sclerites. Of these three, 

 the pronotal lobe, or humeral callosity, is the most conspicuous 

 (Fig. 12). This is an irregularly shaped sclerite somewhat 

 resembling a budding mushroom in general outline. The two 

 humeral bristles (hm) are located on this sclerite, near the 

 dorsal margin. Below this sclerite, and separated from it by a 

 distinct suture, is the proepisternum (pres). This is also 

 irregularly shaped and bears three bristles near its ventral 

 margin, just above the base of the prothoracic coxa. Anterior 

 to these two sclerites another sclerite can be noticed in a lateral 

 view. This is the prodorsum (pd) of Lowne, but it can be 

 better studied in an anterior view. 



