EXPLANATION OF THE ILLUSTRATIONS 
1. Scouta (Dievis) crara ( Fabr.), A male. The insect is enlarged 
approximately three times natural size. The body of the insect is black 
with bristle-like, light brown or yellowish hairs on the thorax, abdo- 
men and legs. 
Drawn from a specimen preserved in the Museum of Comparative Zool- 
ogy, Harvard University. 
2. Opnrys specutum Link, A single flower enlarged approximately 
three times natural size. Sir J. D. Hooker (Botanical Magazine t. 
5844) referred to the labellum of Ophrys speculum as follows: “‘the 
brilliant polished surface of the dise of the lip, which shines like a 
blue-steel looking-glass, edged with gold, and that again set in a rich 
maroon velvety frame, presenting a combination of colours quite un- 
like anything else known to me in the vegetable kingdom.’ 
The relative lengths of the body of Scolia ciliata and of the label- 
lum of Ophrys speculum appear to be so nicely adjusted that the in- 
sect’s head comes directly under the rostellum of the flower when the 
tip of the abdomen is thrust among the hairs near the apex of the 
large middle-lobe. In this regard, and as a product of Natural Selec- 
tion, the labellum of the orchid is a most interesting structure, because 
the marginal portion of the middle-lobe is comparatively smooth and 
sharply deflexed, the elongated hairs ceasing rather abruptly at the 
point where deflexion begins. In the illustration the marginal, smooth 
portion of the middle-lobe is invisible because of its being rolled down- 
ward. The rostellum (represented in the illustration by the two 
rounded structures at the base of the balloon-like anther situated be- 
tween the two short petals) is at just the proper height (about 2 mm.) 
above the base of the labellum where it joins the column, to allow 
the insect’s head to pass beneath it, but in contact with it, when the 
pseudocopulative attitude is assumed. There is hardly any excavation 
at the base of the labellum comparable to the wide-mouthed cup or 
depression in Ophrys fusca and O.lutea, so that the “‘reverse position’ 
is not favored, 
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