104 



CONNECTICUT GEOL. AND NAT. HIST. SURVEY [Bull. 



"ninth" sternite in the housefly. Parker (1914), Hewitt (lOU), and 

 Patton (1932) have interpreted the sixth sternite correctly in their 

 tio-ures of the housefly and other miiscoid flies, but the interpretations 

 of tlie true seventh and eighth segments given by these investigators 

 ai-e \-ery dill'ei-ent from those sugaested here, and the inversion of the 

 eiahth sternite. etc., is not recognized by any of these writers. 



The area labelled 7s in Fig. 13, D, of Hylemyla is regarded as 

 the seventh tergite alone by Cole (1927), who states that 'the seventh 

 sternite is missing" in Ryleimjia, altliougli according to the interpre- 

 tation hore proposed, the area labelled 7-^ in Fig. 13, D. of Hyleniyia 

 is formed by the lateroverted seventh sternite, and only a negligible 

 l)ortion of the area in question is formed l)y the vestigial seventh 

 tergite in Ilylemyla. 



xiwati (1915). Edwards (1920), and Patton (1932) consider that 

 the eighth abdominal segment is lost in the liigher Diptera, and 

 would consequently interpret the synsternito labelled 7s + 8s in the 

 musc'oid fly shoAvn in Fig. 13, E, 'as the seventh '-tergite", largely 

 because tlsis sclerite bears the spiracle of the seventh abdominal seg- 

 ment — although the method by which the spiracle of the seventh seg- 

 ment was brought into this composite plate has been accounted for 

 in another way in the preceding discussion. Snodgrass (1935), on 

 the other hand, evidently does not take into account the occurrence 

 of the seventli spiracle in the synsternite in PoJlenia (Fig. 13, E) and 

 interprets it as the eighth "tergite" in this fly (although the eio:hth 

 segment never bears a spiracle in any male Di])tera) because he con- 

 siders that the seventh tergite is represented by the true sixth tergite. 

 Qt, of Fig. 13, E, and states that the sixth segment appears to be 

 ol^litei-ated in Pollemn. 



The view that the composite synsternite labelled Is A- 8s in the 

 fly shown in Fig. 13, E, represents the "seventh tergite'" alone, appar- 

 ently goes back to Lowne (1890-1895), who interprets the sclerite in 

 question as the "seventh tergite" in the blow^fly, and interprets the 

 ninth tergite as the "eighth" in this insect. Parker (1914) likewise 

 inter]>rots these sclerites as the seventh and eighth tergites in the 

 Sareophagidae, and Hewitt (1914) does the same in the housefly, 

 in which he considers that the surstyli, .s-s, and cerci, ce, of the house- 

 fly shown in Fig. 13, F, represent the divided seventh and eighth 

 sternites in this insect. In a paper published with Carpenter in 1914, 

 Hewitt has attempted to correct his former interpretation of the ter- 

 minalia of the housefly by comparing the parts of the postabdomen 

 Avith those of the warblefly, Hypodemia. The sclerites are very great- 

 ly modified in Tlypodemm, however, and it would appear that Hewitt 

 regards a plate in the terminalia of Hypodcrma which seems to be 

 li()Miol()0;ous with the synsternite bearing the label 7s -\- 8s in Fi|g. 

 14, B, as an "intersegmental membrance", despite the fact that the 

 intersegmental membrances usually do not bear setae, as this plate 

 does in Hypoderma, so that Hewitt's interpretations of the terminalia 

 of these flies evidently need further revising. 



Berlese (1909) and Metcalf (1921) interpret the ninth segment. 



