122 [June, 



naked eye, the hair on the second segment is scanty and very short. 

 The effect caused by the d" Sti/Ioj)s is evidently on the average greater 

 than that resulting from the $ parasite, and in some examples, bearing 

 only a single $ Stylops, the abdominal condition is normal, and were 

 not the head of the Stylops exserted these might pass as healthy bees. 

 No doubt there is every sort of intermediate between the extremes. 



In the $ bee denudation of the abdomen sunilar to that described 

 in the (S may result from infestation by the male Sfylops, while others 

 may hardly show an}^ effect. The characteristic yellow hind tibiae 

 become in some examples entirel}^ dark, or dark with pale tips, the pale 

 face beneath the antennal line becomes frequently entirely clothed with 

 sooty-black hairs. 



In a fine $ bee, affected by a single 5 Stylops, the abdomen is 

 well clothed all over with quite long erect hairs, those at the base pale, 

 but on the apical impression of the 2nd and on all the others the general 

 clothing is black, onl}^ the apical fringes showing an obscure paleness ; 

 the whole face also is clothed with black hairs. So far as the specimens 

 examined are concerned the $ pollinigerous organs in this species are 

 much less deteriorated than in trimmerana ; in fact, in man}^ of them 

 it requires close examination to detect any change at all. The head in 

 stylopized specimens of either sex generally is evident!}^ smaller than 

 in healthy ones, often very conspicuously so. I have examined about 

 thirty stylopized individuals in drawing up these details 



3. A. trimmerana Auct. nee K. — Both sexes show an evident 

 tendency towards decrease in the size of the head, but this is not always 

 noticeable. In normal 6 trimmerana in the South of England the face 

 below the line of the antennae is clothed mainly with brown or j'-ellowish- 

 brown hairs, the abdomen has long pale hairs on the first segment, while 

 those on the second are particularly long and noticeable towards the 

 middle line, so as to form there a more or less e\ddent tuft. The 

 examples most altered b}^ Stylops have the abdomen of a much deeper 

 black than normal, and are very sparsely clothed ; the tuft of the second 

 segment is much reduced in the number or length of the hairs, or in 

 both these respects, and indeed is sometimes all but wanting. The face 

 below the clypeus is clothed altogether with black hairs or the clypeus 

 has many soot}^ hairs mixed with the brown ones. Seven males that 

 I have examined exhibit these characters, and all have carried one or 

 more male Sty lops. 



A common effect of stvlopization in the 6 bee is the presence 

 of a quite conspicuous apical band of appressed hairs on the third and 



