50 BEITISH CICADA. 



Although the phenomenon of parthenogenesis is not 

 involved in the reproduction of Cicadse, I may quote, 

 as relevant in a measure, Mr. McLachlan's remarks on 

 the singular economy of the minute fly, Miaster metro- 

 has. Mr. McLachlan says, " of all the marvels in the 

 history of insects, the agamic production of larvae 

 from larvae, until a brood arises which goes through 

 its ordinary metamorphoses, and results in mature 

 males and females, and thus re-commencing a cycle, 

 is the most astonishing." 



E. Wagner's discovery with reference to Miaster at 

 first was met by the incredulity of even the best 

 physiologists ; but subsequent research has proved that 

 this remarkable phase in insect economy is by no 

 means so exceptional as was at first thought.* 



The reproductive powers of the larvae of some gnats 

 are now recognised, and other examples might be 

 adduced as proof of a remarkable economy. Charles 

 Darwin, apposite to this subject, remarks that some 

 animals show modes of transition through accelerated, 

 or otherwise through retarded, periods of reproduction. 

 If the reproductive powers of larvae through larvae 

 became the general rule, the species, he thinks, would 

 become changed and permanently degraded.! 



At present there are no observations tending to the 

 idea that the Cicadae are at all agamic like the Aphides. 

 Their dimorphic forms may be regarded by some as 

 simple cases of degradation from higher, but less 

 common, existing conditions of existence. Double 

 broods of the Tettigidae may be found in several 

 genera, like Eupteryx, Typhlocyba, and others. 



It is yet open to observers to make out if the genitalia 

 of those forms which hybernate below ground ever in 

 any way differ in form from the summer individuals of 

 the same species. It may be noted that the reproductive 

 larvae of Miaster metroloas continue during the winter 

 season until the spring, when in June the more normal 

 reproduction commences. 



* See Article ' Enc. Britannica,' p. 146. f ' Orisrin of Species,' p. 149. 



