Vol. XXvii] ENTOMOLOGICAL NEWS. 469 



Insects of the Coronado Islands, Lower California. 



I am greatly indebted to the entomologists at the U. S. National 

 Museum for critically examining a number of insects collected by my 

 wife and myself on the South Island of the Coronado group, August 

 21, 1915. They are all additions to the fauna of the islands, but, with 

 one exception, are species previously known to be common on the ad- 

 jacent Californian mainland. The exception is the Hemipteron Tra- 

 pczits, which is not listed at all by Van Duzee in his recent catalog and 

 is also absent from Uhler's list of the Hemiptera of lower California 

 (Proc. Calif. Acad. Sci., IV). 

 Hemiptera (det. Heidemann). Corizus hyalinus Fabr. ; Trapczns Iri- 



inaciilatits Distant. 



Orthoptera (det. Caudell). Mclanoplus cyanipcs Scudd. 

 Hymenoptera (det. Rohwer). Palinodes laeiircntris Cress. 

 Coleoptera (det. Schwarz). Carpophilns pallipenuls Say (very abund- 

 ant), Ipochns fnsciatus Lee., Microrhopala nibrolincata Mannh., 

 Coniontis subpubcsccns Lee., Eulabis rufipcs Esch. Of these spe- 

 cies only the first and the third are in Horn's list of the Coleop- 

 tera of Baja California (Proc. Calif. Ac. Sci., IV). 

 The Coronado Islands appear to represent the tops of a submerged 

 mountain range, and are presumably of recent date, geologically speak- 

 ing. An exhaustive study of their insect fauna would yield results of 

 great interest. The indications are that most of the species (at least) 

 are identical with those of the adjacent mainland, and in a number of 

 cases it is not at all probable that they reached the islands by crossing 

 the water or through human agency. It therefore follows that we have 

 some indication of the antiquity of existing species, and if endemic 

 forms exist it will be interesting to inquire why they have undergone 

 change while the surrounding species have remained unmodified. Such 

 endemic forms may, however, be of two very different types : those 

 actually evolved on the islands, and very close to mainland species, and 

 those which have survived on the islands, having become extinct on the 

 adjacent mainland. The latter, if found, may even represent peculiar 

 genera. Specimens of the species considered identical with those of the 

 mainland should be collected in numbers and carefully compared with 

 Californian examples, with the hope of detecting small or average dif- 

 ferences, indicating the beginning of differentiation. Should such dif- 

 ferences be found, however, it will remain possible that it is the main- 

 land form, not the island one, which has changed from the ancestral 

 type. 



It is especially important that such intensive studies should be begun 

 at once, as many people now visit the islands, and no doubt every year 

 the fauna and flora are modified by the addition of aggressive species 

 following the footsteps of man. T. D. A. COCKERELL, Boulder, Colo- 

 rado, September 2, 1916. 



