Parthenogenesis in. Worker Ants. 661 
There was no sign of wmbratus Ss. The last pupa came to 
maturity on October 22nd, 1909, and was a niger 9. No 
males had appeared. 
The colony passed the winter of 1909-10 in good con- 
dition, the larvae, as usual, remaining unchanged in size till 
the beginning of April 1910. On the 5th of that month 
one larva was nearly full-grown, but it was not till May 
22nd that eleven larvae spun their cocoons. The following 
day this number had increased to twenty, and to more 
than sixty on the 24th. 
The wmbratus queen began to lay again on May 26th, 
some three weeks later than the previous year, but she 
laid many more eggs, and her abdomen became greatly 
distended. 
Finally, on July 2nd, 1910, the first pupae hatched. 
There were six newly-hatched Gs of a pale grey colour at 
11.25 pm. The following day the young ants had not 
quite attained their full colour, but they were unmistak- 
ably niger. On July 7th there were between fifty and 
sixty newly-hatched Gs, none being wmbratus, On the 17th 
I took a number of these young Gs, some still pale, and 
some nearly full-coloured ones, and a few of the old niger 
Ss, and sent them to Dr. Forel for identification. A few 
days later I received an answer from him stating that all 
the ants I had sent him were Lasius niger purus, and 
drawing my attention to Reichenbach’s paper mentioned 
above. 
By Auecust 14th, 1910, all the pupae had hatched, and 
there were about 100-200 eggs, many small larvae, and 
two or three half-grown larvae. All the new Gs were 
of a uniform size, somewhat smaller than the normal 
L. niger. 
During last autumn I talked the matter over with Mr. 
H. Donisthorpe, who kindly communicated with Father 
Wasmann. In his reply, Wasmann suggested having some 
of the 3s dissected to see if any of them possessed a 
receptaculum seninis. Mr. G. H. Grosvenor, of the Oxford 
University Museum, very kindly undertook this task, and 
dissected twelve Gs of various sizes from the colony. In 
none of them was there a receptaculum seminis. 
There can be little doubt that we have to deal here with 
a genuine case of parthenogenesis, confirming Reichen- 
bach’s experiment, and helping to prove that eggs laid by 
3s of some species can produce Gs and not fs. It is note- 
TRANS. ENT. SOC. LOND. 1911.—PART IV. (JAN.) XX 
