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XIII. Remarks on the hairs of some of our British 

 Hjmenoptera. By Edward Saunders. 



[Read March 6th, 1878.] 



(PI. VI.) 



I HAVE recently been examining rather closely some of 

 our British aculeate Hymenoptera, and have been mvich 

 struck with the varieties which appear in the structure 

 of their hairs, and as I do not see that any detailed 

 account has been given by any one of these peculiarities, 

 I propose to 'give the result of the observations that I have 

 made. I know that Beaumur, Mr. Frederick Smith, and 

 others have noticed the existence of plumose hairs on 

 some of the species, but I cannot find that the different 

 variations have anywhere been brought together in a 

 special notice like the present, which I think they deserve. 

 I hoped at first, from the well-marked character of these 

 variations, that they would have been useful in the classi- 

 fication of the genera, &c. ; but although the presence of 

 branched or plumose hairs seems to characterize the sec- 

 tion Anthophila, and to divide it naturally fi'om its allies, 

 yet so far I have found no characters which will serve for 

 further divisions Avithin the section, notwithstanding the 

 great diversity in the structure of the hairs themselves, 

 and also in their relative positions on the insects. I have 

 now examined the hairs of one or more species in almost 

 all the genera of our British Aculeates, and find that in 

 the Heterogyna, the Fossores and the Diploptera, they 

 are all simple, or in some cases twisted, whereas in the 

 Anthophila plumose or branched hairs may always be 

 found, although sometimes mixed with simple ones. This 

 rule holds good even in genera like Prosopis, Ceratina, 

 &c., where the insects have scarcely any hairs, still what 

 there are, maintain the character of the family in being 

 branched or plumose. 



As a rule, the most beautifully-branched hairs may be 

 found round the posterior sides of the metathorax, but in 

 some genera, such as 3Iacropis, Dasypoda, and in some 

 species of Andreno, they occur on the scopiB of the hind 

 legs, and in Chelostoma are found on the pollen-brush of 

 the body. The diversity in the shape of the pollen hairs 



TRANS. ENT. SOC. 1878. — TART II. (jULY.) N 



