V^ol XX vi] ENTOMOLOGICAL NEWS. 129 



with the species and that it was proved able to ahemate this 

 mode of reproduction with the ordinary kind according to the 

 nature of its host, this though a wonderful fact, would certain- 

 not form a basis for specific differentiation. For the very 

 definition of species would make it necessary that neither 

 mellitor nor dorsata bred with one another or were identical 

 in hereditary elements: for if this is so. the habits may vary 

 infinitely without changing their essential specific unity. We 

 know of so many instances in insects of great variability in 

 habit of knotitt s|>ecific units, and of so few or none where 

 known specific units do not var)-. that it would be extremely 

 hazardous, to say the least, to base two species on the mere 

 fact that a diflFerence in habit was present. Before such a 

 thing is done it will be necessary to change the deBnition of a 

 species, and even that will not eliminate the fact that in nature 

 there occur such things as a population of more or less defin- 

 itely limited individuals which are all descendants from a 

 oonunon stock. 



flsasonil NotM on lasscts In Virginia. 

 At Blacksburg in 1901. butterflies had abnost stopped flying 

 by October 12th: by the 25th Diptera and Ilymcnoptera on 

 the wing were liecomtng scarce; on November «>, however, 

 swarms of Mycetophilidae were observed. Then Orthoptera 

 were conspicuous ; Thyrtdopteryx and CaUosamia had cocoon- 

 ed. On March 20th following, the first buttcrly was observed, 

 probably I'anessa antiopc. On April 11. the eggs of aphids 

 were hatching ; an adult of V. a$Uiopa was observed and also 

 several moths. On .April 18, Diaslropkus nebulosus was 

 emerging (indoors) and the eggs of Matacosoma amencana 

 were hatching, the nests now appearing like cobwebs ; the cater- 

 pillars then were about 6 mm. long and were feeding upon 

 just o{)ening buds. On .April 22, Carpocopsa pomoneUa was 

 observed depositing eggs (Professor Alwood). On the 30th. 

 Pieris rapae was ovipositing onto young cabbage plants (2-3 

 inches high) ; eggs of CoccineUidat observed May 2, 1902, 

 Actios luna had not emerge<l : Mcdacosoma amcricana now 

 conspicuous in their nests. The following day, adult Schisto- 



