98 Psyche [June 



tion for a much longer period, if not indefinitely. Earlier investi- 

 gators, like Bonnet .(1745) and Kyber (1815), had previously ob- 

 served the maintainence of continuous parthenogenetic reproduc- 

 tion in various species of aphids for long periods of time. 



Males and oviparous females are known to be produced only 

 under the prolonged influence of extremes of temperature, such 

 as during the winter in temperate climates, and, as certain inves- 

 tigators claim, in cases of scarcity of food. Observations on this 

 modifying action of climate and food, according to Buckton (1882, 

 p. 109) were reported by Bonnet in 1745, and later confirmed by 

 De Geer in 1773. 



From our somewhat fragmentary knowledge of tropical aphids, 

 we may tentatively infer, in the absence of more definite evidence 

 to the contrary, that representatives of this family reproduce 

 exclusively by parthenogenesis in warm countries. The following 

 table gives a partial list of the localities in which a continuous 

 parthenogenetic reproduction throughout the year has been ob- 

 served. It will be noted that the various localities included in 

 the list are characterized either by the total absence of winter or 

 by a relatively mild climate. 



LOCALITY SPECIES AUTHOKITY 



France (Orleans) Aphis rumicis L. Gaumont (1913) 



Germany (Bremen?) Hyalopterus trirhodus 



Walk. Borner (1914) 

 Rhophalosiphum lac- 



iucce Kalt. ditto 



Holland Aphis gossypii Glov. van der Goot (1915) 



Aphis hedercB Kalt. ditto 



Aphis abietina Walk. ditto 



Aphis immicis L. ditto 



Eriosoma lanigera Hausm. ditto 

 Macrosiphum granarium 



Kirby ditto 



Myzus persicoi Sulz. ditto 



India Aphis hrassicce L. Maxwell-Lefroy (1907) 



Aphis cardui L. var. ditto 



Aphis gossypii Glov. ditto 



