Maskell. — On Coccididoe. 47 



Aphides species which are truly liermaphrodite. I beheve, 

 however, that, as far as any thorough investigations have yet 

 been made, the so-called parthenogenesis is but the continuous 

 action of an original sexual act between a true male and a 

 female, acting through a certain number of generations, after 

 which the race would be extinguished without a repetition of 

 the sexual act.''' This form of generation (which undoubtedly 

 is itself sufficiently wonderful) appears to have been satis- 

 factorily observed in Aphides and in certain species of Diptera ; 

 while, as regards Coccids, something analogous has already 

 been announced in the case of Lecanium hesijeridum, by M. 

 Moniez (Comptes Eendus de I'Acad. des Sci., 1887), where 

 the male is stated to remain in the body of its female parent, 

 and, itself in the larval stage, to ivipregnate tlie female larvcR 

 before they emerge. As far as the females are concerned, Sh' 

 E. Owen has accounted for the facts observed (Disc, on Par- 

 thenogenesis, 1849), by a theory of the retention of the power 

 of reproduction in some of the "nucleated cells " of the first 

 female of the series. Of course, the explanation would not 

 touch the point of the generative power in the male of 

 L. hesperidum existing only in its earliest and quite incomplete 

 stage. 



However, although, in the case of Aphides, the attention of 

 entomologists has, ever since the days of Eeaumur, been 

 directed to this phenomenon of unisexual generation, very 

 little has been known or written about it in connection with 

 Coccids. Incidental remarks may be found in various ento- 

 mological and other works to the effect that the Homoptera 

 as an order are endowed with this special power ; but it 

 would seem that these are simply generalisations from the 

 particular case of Aphides ; and I am not aware of any writer 

 on Coccids who has mentioned an actual instance for any 

 species of that family. It will therefore be not uninteresting 

 to note here a case under my own observation, and undoubtedly 

 clear. 



The first examples of G. conipressuvi wdiich I received (in 

 1890) from Mr. Eaithby were females of the second stage on 

 pieces of bark, each resting in its mass of excreted w^ax. 

 Some of these I dissected or mounted ; others I placed in my 

 cabinet in the usual way— with a pin through the bark. My 

 experience of insects in this stage is that in the great majority 

 of cases they remain i)i situ, and in a few days die : adults I 



* In PsTjcJic for September, 1891, p. 150, I find it stated that "to a 

 description of a hermaphroditic spider Bertlcau appends a catalogue of 

 recent cases, and states that 361 liermaphroditic Arthrojjoda are now 

 known, of wliich .... 349 insects." I do not know where the 

 paper referred to is to be found ; but in the list given in Psyche no men- 

 tion is made of HomoiHcra, 



