1G6 J»iy. 



was said earlier in these notes, except that further experience has 

 (inly confirmed and strengthened one's faith in it. 



Frequent reference will be made to the male genitalia. Here 

 again two chief types are met with, one in which the hypopygium is 

 small, the other in which it is large ; the first is associated with a 

 short and stout abdomen, very feminine in build ; the second with a 

 long and slender one. In the smaller type the hypopygium is usually 

 concealed within the last abdominal segment, leaving visible only the 

 anal protuberance (in this case always small) ; but shouM it be 

 exposed, it looks like a small body stuck on to the blunt-ended 

 abdomen. In the larger one, on the other hand, it is usually more or 

 less exposed, and has the appearance of a natural prolongation of the 

 abdomen, whilst the anal organ, as a rule, is large There is, however, 

 considerable difference in >\ze among the large hypopygia ; hence it 

 will be convenient to subdivide them into '■ large " and " medium or 

 moderate." In the former both the hypopygium itself and the 

 internal parts are usually fully exposed, the anal protuberance at the 

 same time being large and conspicuous ; in the latter the exposure is 

 less complete, and the anal protuberance of more moderate size. 

 These internal parts or, as I shall term them, " subanal body," are 

 extremely complex in structure, and are connected with the intro- 

 mittent organ. No doubt they would afford excellent points of 

 distinction under the microscope, but are too minute for ordinary 

 descriptive work. On I he under-side of the hypopygium and close to 

 the edge of the last abdominal segment is often present a chitinous 

 projection of very varied form, sometimes flap-like, sometimes like a 

 slender prong, simple or forked, or of much more complex shape. 

 It may be called the ventral process, but it needs a full exposure of 

 the genitalia to render it visible. The shell of the hypopygium is 

 occasionally cut into lateral processes or lamellae, which are either 

 symmetrical or the reverse. It is by no means a common condition, 

 and is almost confined to some of the species in Section B, being one 

 of the points which show their relationship to Group I. Occasionally, 

 also, one or more conspicuous bristles spring from its lower edge on 

 each side, and serve as good specific characters. Lastly, it is as well 

 to take note of a pair of curious curved bristles at the extremity of 

 the anal protuberance, since their presence at once settles the 

 question — where if might otherwise be doubtful —of sex, and whether 

 the small object peeping out from ihe end of the abdomen be the point 

 of the ovipositor or of the anal organ. 



A character also of much importance is the row of bristles or 



