ART. 4 



BEETLES OF THE GENUS COCCINELLA DOBZHANSKY 



29 



thoroughly. On the other hand, only one of these species — namely, 

 transversoguttata — extends its distribution to the southern limits of both 

 nearctic and palaearctic regions; that is to say, most of the species 

 in common to both regions are distributed only in the northern part 

 of the hoiarctic region. The accompanying table shows the subdivi- 

 sion of the genus into groups, and the correspondence between the 

 nearctic and the palaearctic faunas. 



Group 



novemnotata 



transversoguttata. 



septempunetata.. . 



difflcilis 



trifasciata 



undecimpunctata. 



Nearctic species 



f novemnotata Herbst 



Iprolongata Crotch. 



(transversoguttata Falderman. 

 johnsoni Casey 



Icalifornica Mannerheim 



InivJcoia subspecies monticola Muisant. 



[difficilis Crotch.. 



suturalis Casey 



trifasciata Linnaeus. 



hieroglyphica subspecies tricuspis Kirby. 

 (undecimpunctata Linnaeus 



1::::::::;:::::::::::: :::::::::::: 



Palaearctic species 



divaricata Olivier. 



i transversoguttata Falderman. 

 magnopunctata Rybakow. 



[septempunetata Linnaeus. 

 Inivicola Menetries. 

 Ireitteri Weise. 

 [saucerottei Muisant. 



Jtianshanica Dobzhansky. 

 liranica Dobzhansky. 



[trifasciata Linnaeus. 

 <quinquepunctata Linnaeus. 

 Ihieroglyphica Linnaeus. 



{undecimpunctata Linnaeus, 

 pontica Dobzhansky. 

 miranda Wollaston. 



The specific diversity of the genus Coccinella is concentrated, in 

 North America, in the region between the Rocky Mountains and 

 the Pacific Ocean. There is no species, except undecim'punctata L., 

 that lives in North America, and that is not found in this region. 

 East of the Hocky Mountains there are found only five species, and 

 these are the species common to the nearctic and palaearctic regions 

 (see above), i. e., the widely distributed hoiarctic species. As men- 

 tioned above, these species are chiefly northern in their distribution. 

 Hence, the fauna of the southeastern United States is very poor. 

 The only species found in this region is novemnotata Herbst. The 

 presence of a clear center of the specific diversity in the nearctic 

 region has no parallel in the palaearctic. Indeed, in the palaearctic 

 one may point to at least two separate such centers; one in the 

 region of Mongolia, Tsaidam, and Kuku-nor and the other in the 

 mountains of Russian Turkestan (especially the Tian-Shan system) 

 One may also note that all the species that are w^idely distributed 

 in North America form separate subspecies in the regions lying west 

 of the Rockies. 



The second outstanding feature of the distribution of Coccinella 

 is the decrease of the number of species from north to south. The 

 fauna of Mexico, though very little known, is certainly poor. In the 

 south the genus Coccinella is replaced by the closely related Cyclo- 

 neda Crotch. The center of the specific diversity of Cycloneda lies 

 in Central and South America, where it, and some related genera, 

 replace Coccinella completely. 



