1880 .] 
127 
PARTHENOGENESIS IN THE COLEOPTERA* 
BY J. A. OSBORNE, M.D. 
In the “concluding remarks” in liis treatise on “ Wahre Parthe- 
nogenesis ” (185G), von Siebold says, “ Es ist daher jetzt Aufgabe der 
Entomologen, nach weiteren Beispielen von Parthenogenesis in dcr 
Insektenwelt zu forschen;” and on the last page (237) of his “Beitriige 
zur Parthenogenesis,” published fifteen years Jater, he expresses the 
conviction that many facts relating to this phenomenon are still to be 
discovered. The instances of true parthenogenesis discussed or 
referred to in these two works relate to insects of the Orders of 
ITymenoptera and Lepidoptera , and to some crustaceans, including 
viviparous agamogenesis, however, as parthenogenetic, the orders 
Hemiptera and Diptera also furnish examples of this mode of repro- 
duction ; and for its occurrence in at least one genus of the Trichoptera 
I have the authority of Mr. B.McLachlan, E.B.S.t The possibility of 
parthenogenetic reproduction in the Coleoptera rests only, so far as I 
am aware — see “ Comparative Embryology,” by E. M. Balfour, vol. i, 
p. 64 — on the single instance communicated by me to this journal last 
year (Nature, vol. xx, p. 430), and this being so, it seemed desirable to 
make sure of this point by further research during the season now 
almost past. Accordingly, I have this year kept a considerable number 
of females of G-astropliysa raphcini , laying unimpregnated eggs, and 
with results which have not only confirmed the previous experience, 
but much extended it, as I am at present in possession of a living beetle 
reared from a parthenogenetic ovum. With your permission I shall 
now endeavour as briefly as possible to give those circumstantial details 
without which a bald statement of results would not carry with it a 
rational conviction of the accuracy of my observations. 
From beetles gathered in the beginning of last April I had a batch 
of eggs on the 7th, which hatched out on the 2 1st of the same month, 
and on May 13th— 15th yielded about thirty pupae, which were 
immediately put into separate vessels. On the 20th — 22nd appeared 
the imagines, of which ten subsequently turned out to be females, and 
were placed together in pots, but not before the greatly enlarged 
abdomen had given unmistakable evidence of their sex. The first 
eggs, three batches, were laid on June 2nd (so completing the cycle, 
from egg to egg, in fifty-six days). On the 12th of the month I found 
^Re-printed from “ Nature,” Vol. xxii, pp. 509, 510. .... ...... 
t I fen- Dr Osborne has somewhat misunderstood some remarks of mine m a letter to him. 
T am very strongly disposed to believe that parthenogenesis exists in certain species of the genus 
Anatcnia in Trichoptera, but it is not proved. All wo know is that although the females occur in 
abundance, no male has yet been discovered. This particularly applies to A. muhebns and A. 
arctica. — R. McLachlan. 
