332 Mr. Newport on the Natural History 
characterized in the Transactions of this Society as the “ STREPSIPTERA," from 
the twisted form of the rudimentary elytra with which the male individuals 
are furnished. Rossi's insect had in the meantime been examined by Pro- 
fessor Jurine, who distinguished it from another species, also found in the 
wasps. Mr. Kirby and Dr. Leach afterwards each described additional spe- 
cies, Stylops tenuicornis and Stylops Kirbii; and Mr. Curtis and Mr. Dale 
each characterized a new genus, Elenchus and Halictophagus. These were 
followed by new species by Mr. G. R. Gray, Stylops Childreni ; by Mr. Picker- 
ing, Stylops Spencii ; by Messrs. Templeton and Westwood, Elenchus Temple- 
tonii; and by Leon Dufour, Xenos sphecidarum,—the whole of which were 
found to be parasitical in their habits. Yet none of these naturalists were 
able to ascertain anything perfectly conclusive respecting the sex of the 
species they had captured. Professor Peck had however suspected that the 
four specimens of Xenos obtained by himself were males; although Rossi 
imagined that the winged specimens which he obtained were of both sexes. 
From what is now known we are satisfied that this was an error. It has been 
well ascertained by Dr. Siebold that the male sex only is winged. This fact 
established, raised at once a difficulty in understanding in what way these 
insects are propagated, and by what means the females are brought into 
communication with the species of bee or wasp on which they are parasites. 
M. Klug, in 1810*, appears to have been the first to observe a fact that has 
since led the way to an explanation of this problem in their natural history. 
He remarked that the Strepsiptera are sometimes covered with little hexa- 
pods, which he regarded as parasites. 
In December 1834, Mr. Pickering, in this country, obtained froin its nidust 
in a sand-bank a living specimen of Andrena tibialis, which had recently 
assumed the imago state, and had never left its cell. In this specimen he 
“ observed some protuberances between the abdominal segments, and think- 
ing the bee might be stylopized, endeavoured to remove one of these swell- 
ings," out of which be obtained a living (male) Stylops (Stylops Spencit), 
which, like the insect.it infested, had recently become perfect.. This fact, as 
* Nachricht von einen neuen Schmarotzer insekt auf einer Andrene. Magazin der Gesellschaft 
naturforschender Freunde zu Berlin, 1810, p. 266. 
T Trans. Entom. Soc. Lond. (Proceedings, Jan. 5, 1835), vol. i. p. 164, 
