Aphididae of Foamosa — 4. g5 



Peninsula and other adjacent regions, it will probably be proven that the aphid 

 fauna of Formosa is more closely related to that of Southern Asia than to that 

 of Japan. It is very interesting that PterocMorus tropicalis v. d. Goot found 

 in India, China and Japan is not seen in Formosa. 



(4) Up to the present time about 3740 species of plants arranged in 

 about 1200 genera have been recorded from Formosa. Of these plants about 

 260 species in 179 genera are now known to be fed upon by aphids in Formosa. 



(5) Near Taihoku almost all aphids are viviparous throughout the year, 

 without producing sexual forms; and CaUipterus hahawaluokalani Kirk, is the 

 only species in Formosa, which is. at present, known to produce the males and 

 oviparous females in the fall and to pass the winter only in the egg stage. 



Shivaphis celt! Das on old Celtic sometimes produces males, as well as 

 oviparous females, in the fall, though the same species on younger host-trees is 

 continuously viviparous, without producing the true sexes, even in the winter 

 (see "Aphididae of Formosa," part 2, p. 132 and part 3, p. G6). An oviparous 

 female has been discovered in Neophyllaphis podocarpi Takah.. although the 

 males have never been collected (see "Aphididae of Formosa", part 2, p. 129). 

 A few males of Myzus pcrsicae Sulz. (-'Aphididae of Formosa", part 2, p. 21), 

 Hyalopterus chenopodii Schrank and Brachycolus heraclei Takah. (see "Aphididae 

 of Formosa", part 3, pp. 48 and 50) have been found near Taihoku, their 

 oviparous females, however, having never been discovered in Formosa. 



(6) There are numerous natural enemies of these insects in Formosa, but 

 it is a very interesting fact that no Hymenoptera parasitic upon Oregmd have 

 ever been collected there. 



