346 



PSYCHE. 



[May iSgo. 



Fig. 4. 



The extensile ovi- 

 duct of the fly is a very 

 pretty object when 

 fully spread out under 

 the microscope. It is 

 seen that at each seg- 

 ment is a broad belt of 

 closely laid scales and 

 that strong chitinous 

 rods support the tube 

 and probably aid in the 

 expulsion of the o\'um. 



I have examined this 

 organ in a number of 

 diptera and find it dif- 

 ferent in detail in each 

 species. 



The genitalia of the 

 male are quite compli- 

 cated, and in this 

 species comparatively 



Fig. 5. 

 larger and more easily studied than in 

 S. calciti'ans or in Musca dojnesticai 

 both" of which differ very decidedly 

 from our species.'^ The figure is from 



a camera drawing and no attempt has 

 been made to symmetrically arrange the 

 parts. The broad uncus with its 

 spreading and elongated lateral angles 

 at tip is supported at base by two smaller 

 processes with rounded, curved tips. 

 The harpes are membranous rather 

 than chitinous, and are only apparently 

 dissimilar, the hook like process of the 

 left figiu'e being concealed on the right. 

 So the accessory clasper at the base of 

 the right harpe is not shown on the left, 

 though it is also present. A close study of 

 these organs in the diptera will undoubt- 

 edly show many interesting structures. 

 The mouth parts of the larva were 

 also studied and the figured structure was 

 presented. The outward appearance is 

 that of a ringed lip with a central open- 

 ing behind which rise the fleshy emi- 

 nences which bear the small palpi. 

 The lips are made up of the usual tubu- 

 lar structure, the margins open and 

 giving the appearance shown at 3 in 

 figure 6. It seems there as if the tubes 

 were made of an endless piece of struc- 

 ture the material being drawn from one 

 to the other. When properly treated 

 the tissue becomes transparent and the 

 chitinous sucking or pumping stomach 

 is brought into view, lying mostly 

 within the first segment. This organ is 

 roughly six-sided, three of the plates 

 distinctly chitinous, the others more 

 membranous and furnished with power- 

 ful muscles — in fact muscular bands are 

 attached at all angles of this structure and 

 thus the pasty mixture upon which the 

 larva subsists is drawn into the stomach. 



