NO. 1GS7. THE THORAX OF IXFlECTFl—FiXOnQRASS. 569 



that it can not be doubted that the sclerite in question belongs to the 

 cpisternuni. Sonie authors have regarded it as a part of the meso- 

 steruum. Among the hitter are Lowne (1902), who calls it the " lat- 

 eral plate" of the niesosternum. Ilewett (1907) interprets it in 

 lli(> saiuc way. Ilannnond (ISSl) identifies it as the " parapterum," 

 but this is certainly stretching homologies too far, esjoecially since 

 a true i3rei)arapterum is present in the mesothorax (174, 170, 178, P) 

 of Iloloriiftia and two in that of Tahanus (179, 1/*, 2P). Berlese 

 (190G) regards the i^late as the mesoepisternum, as also does Cramp- 

 ton (1909). A comparison of figs. 174 and 179 certainly suggests 

 nothing else than that the mesoe]nsternum {PJpn.,) of the former is 

 simi^ly divided in the latter into two plates {eps.^ and Kps„). 



('). Mesonotum very large (174, 175, 179, 180) and in Iloloritfiia 

 (175) definitely subdivided into prescutum (;>-sr=), scutum (.srO, and 

 scutellum (srl)^ but in Tabanus (179, 180) first and second parts 

 not so distinctl}^ separated {pse, set). The scutum carries the anterior 

 notal wing processes (AN^P) and the scutellum the posterior wing- 

 processes (PN^P) and axillary cords (AXC). 



7. Mesopseudonotum very large in Ilolorvsln (174, 175, PN.)^ con- 

 sisting of median and two ]at(n'al subdivisions, the " mediophragmite" 

 and " i^leurophragmites " of Crampton (1909), the latter connected 

 with epimera (174, i?;_>w). Present in pupa (173) as plate {PNS) be- 

 tween the two wing-bearing nota {N^^ N^). In Tabanus (179) 

 mesopseudonotum {PN^) narrow, reaching undivided down the side 

 to ej)imerum (Epm.^), carrying posteriorly an extremelj^ large 

 phragma (Pph.,) extending downward and posteriorly into abdo- 

 men, making a large convex wall almost shutting off the cavity of 

 abdomen from that of thorax. 



8. Metathorax always reduced, but w^ith the two principal pleural 

 plates well developed (174, 177, 179 Eps.,, Epm^) and forming a 

 normal w^ing process {^yP^) supporting the halter (HI), in everyway 

 comparable with the parts of the mesothorax (17G, 178) except that 

 the preparaterum (P) is lacking. Metanotum (174, 179, N..) re- 

 duced to a narrow band. Metapseudonotum (PN^) present and 

 continuous with the epimera (Epm.^). 



9. Axillaries normal, present in both wing (210, 212) and halter 

 (211). The detailed structure of the base of the latter (211) leaves 

 no doubt that it is simply a modified wing, while a study of a Tipulid 

 pupa (173) shows that the halter (W.,) is truly Aving like in its origin. 



10. Tegula (210, 212, Tg) developed as a large hairy scale covering 

 humeral tingle of wing. 



11. Alula a specially developed lobe or lobes of the axillary mem- 

 brane of the wing (212, Al) bordered by the axillary cord (AxC). 



