ANTENNA OF THE HOJSTET-BEE. 87 



joint ill its proper place. The membrane which joins the scape 

 with the second segment has some very minute yellow dots upon 

 it, which terminate in short sharj) points or hairs. The markings 

 on other segments are described by Dr. Hicks in these words : — 

 "E^ery structure consists (viewed from above) of round trans- 

 parent spots about YTSU ™ch in diameter, but on a side view they 

 are seen to be depressions of the surface, the internal wall being 

 perforated, with a thin membrane closing in the perforation, which 

 is probably the external layer of the antennal wall continued over 

 it." This is quite accurate as regards those segments in the 

 middle portion of the flagellum, but as tliey approach the anterior 

 end, and especially in the last segment, they are much more 

 complicated. On the end segment there seem to be five distinct 

 sorts of structures. 



The first, when viewed from above, appear as openings in 

 the wall of the antenna, which, on a broken edge, are seen to be 

 covered by a membrane. Upon focusing down to the general 

 surface of the antenna, this suddenly opens into a wider space 

 surrounded by a ring of dark dots ; and on continuing the 

 focusing, the opening again contracts to a size smaller than the 

 opening on the outer wall. If, however, a fresh antenna be ex- 

 amined, under a ^-inch object-glass, without any -preparation and 

 with light directed along it from the anterior end, the structure 

 appears as in fig. 5 (sectional view a, fig. 6). The ujDper membrane 

 is supported upon a rim, and presents somewhat the appearance 

 of the lid of an oval hunting- watch, the small glass representing 

 the upper membrane. 



The second structure is found interspersed amongst those just 



described, and consists of smaller openings, which, instead of being 



closed in at the top, are drawn out into a pointed hair (b, fig. 6). 



The third structure consists of hairs springing from the base 



of still smaller pits (c, fig. 6). 



The foregoing coincide very closely with some of the structures 

 described by Dr. Hicks in other insects, the first being similar 

 to that of the antenna of Andrena fulva; but he does not give 

 any description of its appearance by direct light. The second 

 and third are similar to structures found by him in the antenna 

 of Geotriipes stercorarius. I give a diagrammatic figure of them 

 in section in fig. 6. 



The fourth structure is found only on a ridge on the end of the 

 last segment, fig. 7. The appearance is that of hairs sunk in pits 



