Coloration and Development of Insects. 79 



larly, yet I have only got four males during several years. 

 Now males are, as a rule, much easier bred than females 

 owing to their smaller size, and to their appearing seven 

 or eight days earlier than the females, so that, if they were 

 at all common, the chances are all in favour of the 

 observer rearing them. 



The phenomenon would appear to occur with closely 

 allied species in all the genera. Thus we have (mentioning 

 only common species) Heniichroa rufa with the ^ unknown, 

 and H. aim with it very rare, while the closely allied 

 Dineura verna has no male. Then there are Poecilosoma 

 jndveratum and P. luteolum, and two or three species of 

 Fenusa with no known males ; the same is the case with 

 Blennocampa alh'vpes and B. eplilppium, while the closely 

 allied B. fascipennis, Fall. (Ititeiventris KL), has the ^ 

 very rare. So it is with the too common Erlocaynpa 

 adumhrata, while, as stated already, E. ovata is unisexual. 

 Again, the males of Hoplocampahrcvis, KL, audi/, rutili- 

 cornis, KL, have not been described, while of the large 

 genus Nematus we have N. Erlchsoni, Htg., andpa??/- 

 diventris ; leucotrochus, H., and conductus, Ruthe ; and 

 (as before mentioned) palliaiiis, curtispina and miliaris. 



Note. — Since writing the above paper, Mr. Meldola has directed my 

 attention to a paper of bis (Proc. Zool. Soc, 1873. p. \nij) wherein he has 

 given a similar explanation of the change of coloration in larvte before 

 pnpation to that stated on p. 71. Mr. Meldola gives as examples of this 

 habit various species of Lepidoptcm. 



TRANS. ENT. SOC. 1880. — PART IT. (jTJNE.) 



