72 



Parfitt, with reference to which subject Mr. Westwood denied thai he had, as stated, 

 informed Mr. Parfitt that this species was new to Science. 



Mr. Newnaan communicated the following: — 



A Word on the Pseudogynous Lepidoptera. 



" The attention of entomologists has lately been directed to a phenomenon, which, 

 under a severe scrutiny, seems to have arisen from the questionable position of an ex- 

 ception into the importance of a normal law. I allude to Agamogenesis. I have now 

 to invite attention to what might be termed a compensating or balancing phenomenon, 

 — a phenomenon which, instead of providing an unlooked-for multiplication of life, 

 seems to dry up the source of life. This phenomenon is Pseudogynism, or the occur- 

 rence of false or unproductive females. It is very familiar to the breeders of domestic 

 cattle, by whom such false females are called free martins. All attempts to overcome 

 their sterility having of course been unsuccessful, they have been abandoned, and the 

 beasts have been at once fattened for the butcher. I think entomologists have not 

 hitherto recorded the existence of the same free marlinism, or pseudogynism, among 

 moths ; it is nevertheless a fact that it exists to a very great extent, more than half 

 the individuals of certain species proving sterile females. The first observation I 

 made on this subject was in 1846, on an autumnal-disclosed specimen of Orlhosia 

 instabilis, the abdomen of which was opened, with a view of ascertaining the state of 

 the eggs on the occasion of this unwonted first appearance on the stage of life. Eggs 

 there were none ; the abdomen was a hollow cylinder, without any trace whatever of 

 an ovary, or indeed of any portion of the ordinary contents. The next observation 

 was made on an example of Sphinx Convolvuli taken the same year. The captor slit 

 open the abdomen longitudinally, from the anus to the insertion of the legs, intend- 

 ing to remove the contents prior to drying the insect for the cabinet. In this case 

 also the abdomen was perfectly empty. My notes on this subject were laid by, but 

 not forgotten, until 1851, when I received a notice from the South of France respecting 

 Deilephila Celerio, which that year appeared in profusion in the months of September 

 and October, the report stating that all the females were barren. This of course 

 afforded more food for reflection, and in 1852 I sacrificed a number of Sphinx Ligus- 

 tri and of our three species of Smevinthus, thinking to find and investigate a similar 

 phenomenon. In this I was disappointed : all the specimens were summer-dis- 

 closed, and all had the ovaries distended with mature eggs. I was now inclined to 

 assume that the previously observed facts were accidental or exceptional, and not to 

 be recorded as the results of any universally operating law ; but, last autumn, that is 

 the autumn of 1856, the subject was again brought before me by the examination of 

 recently disclosed females of Acherontia Atropos, which proved perfectly sterile. 

 Now, as I knew there was a summer disclosure of this insect, giving rise, among the 

 raw recruits of our science, as in the case of hybernating Rhamni, to a double-brooded 

 hypothesis, I could not but be struck with a phenomenou that began to assume the 

 weight and importance of a fixed law. It appeared, on comparing and arranging a 

 series of observed facts, 1st, that certain Lepidoptera had two periods of disclosure, 

 the aestival and the autumnal ; that the summer batch, produced while the leaves were 

 in full vigour and afforded abundant food for the larva), was fruitful ; the autumnal 

 brood, disclosed when the leaves were about to fall, was barren. The autumnal brood 

 seems only to occur in cases where the number of the specimens has been much larger 



