1908.] NATURAL SCIENCES OF PHILADELPHIA. 487 



species so tabulated, six (Hetcerina cruentata, Argia fissa, A. extranea, 

 Acanthagrion gracile, Ischnura ramhuri var. credula, Perithemis domitia 

 iris) occur in all of the four zones in which these insects have been 

 collected, viz. (names as given in Sapper's, 1895, map for Guatemala) : 

 1. Savannas and stretches of primeval forest alternating (wet), 2. 

 Tropical and subtropical rainy forests, 3. Oak and pine forests of the 

 hot and temperate climates, 4. Grass- and bush-steppes and dry- 

 forests. Twenty-four species {Hetcerina tricolor, H. macro-pus, Argia 

 pidla, A. indicatrix, A. oenea, Enallagma caecum novce-hispanice, 

 Telebasis salva, Leptohasis vaciUans, Uracis imhuta, Orthemis ferru- 

 ginea, 0. levis, Erythrodiplax funerea, E. umbrata, E. ochracea, 

 E. connata var. d, Dythemis velox, D. cannacrioides, Brechmorhoga 

 prcecox, B. inequiunguis , Macrothemis pseudimitans, Paltothemis 

 lineatipes, Sympetrum illotum virgulum, Erythemis verhenata, 

 Lepthemis vesiculosa) appear in three zones. j\Iore than thirty species 

 (including such endemic forms as Cora marina, Heteragrion tri- 

 CiUulare, Argia frequentula, Telebasis digiticollis, Neoneura 

 amelia, Erpetogomphus viperinus, Brechmorhoga pertinax) are 

 common to zones 2 and 4, but not to others. 



This does not necessarilj^ mean that a correlation of Odonate species 

 with vegetation formations does not exist. It may be that slight 

 local differences of too small an area to be shown on the maps employed, 

 or that our data based solely on the imagos, not on the larvae, are 

 responsible for its apparent absence."* 



The few instances, above referred to, in which some correlation 

 seems to exist are those of certain Odonata occurring in the tropical 

 and subtropical rainy forest areas, as the species of Protoneura, Para- 

 phlebia, Argiallagma, Ephidatia and Nephepeltia, and, less certainly, 

 of other genera of the legions Podagrion and Protoneura. From 

 the notes of collectors which have been quoted under the respective 

 species*'^ it would also appear that members of the legion Pseudostigma 

 are dwellers in forests,**^ although not necessarily wet forests. 



" Those disposed to make further researches as to the existence of such cor- 

 relations will doubtless find assistance in Senor Jose Ramirez' "La Vegetacion 

 de Mexico" (Anales, Ministerio de Fomento, Repiib. Mex., XI, pp. 227-489, 

 189S). His botani co-geographical regions, however, are not shown on any 

 of the maps accompanying his memoir. 



'^ Biol. Cent.-Amer. Neurop., pp. 53, 56, 353. Cf. also Selys, Mem. Couron. 

 Acad. Sci. Belg., XXXVIII, p. 9, footnote, 1886. 



" With the clearing of these forests, now apparently in progress (cf. Belt, 

 Naturalist in Nicaragua, pp. 185-6; Sapper, Mittelamerikanische Reis. u. Stud., 

 pp. 308-9), we must probably expect .the disappearance of these Odonata. 



