Vol. XXvi] ENTOMOLOGICAL NEWS. 129 



with the species and that it was proved able to alternate 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 known specific units, and of so few or none where 

 known specific units do not vary, that it would be extremely 

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

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

 thing is done it will be necessary to change the definition 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 

 common stock. 



Seasonal Notes on Insects in Virginia. 



At Blacksburg in 1901, butterflies had almost stopped flying 

 by October I2th; by the 25th Diptera and Hymenoptera on 

 the wing were becoming scarce ; on November 9, however, 

 swarms of Mycetophiliclae were observed. Then Orthoptera 

 were conspicuous; Thyridopteryx and Callosainia had cocoon- 

 ed. On March 2Oth following, the first butterly was observed, 

 probably Vanessa antiopa. On April n, the eggs of aphicls 

 were hatching; an adult of V. antiopa was observed and also 

 several moths. On April 18, D last ro pints nebnlosits was 

 emerging (indoors) and the eggs of Malacosoma aincricaiitt 

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

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

 just opening buds. On April 22, Carpocapsa poinonella was 

 observed depositing eggs (Professor Alwood). On the 3Oth, 

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

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

 Aetias lima had not emerged: Malacosoma anicn\\tini now 

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



