232 NEUROPTERA. 
(1889) ; Cat. Odon. p. 25 (1890); Calvert, An. Mus. Nac. Buenos Aires, vil. p. 34 
(1899). 
Neocysta, Kirby, Trans. Zool. Soc. Lond. xii. pp. 263, 300 (1889) ; Cat. Odon. p. 35 (1890). 
Although the types of these two nominal genera, Orthemis ferruginea, ¥., and 
Neocysta attenuata, Erichs., present quite a different appearance, they are so connected 
by intermediate species (as may be seen by studying the synopsis below) that’ they 
must be placed in the same genus*, Perhaps the most striking of these differences is 
that of the broad abdomen of ferruginea and the slender hind body of attenuata. 
In spite of this, Mr. Kirby’s remark (Trans. cit. p. 302) on Orthetrum (“The con- 
spicuous differences in the shape of the abdomen visible in the groups typified by 
Libellula sabina.... &c. ....are unaccompanied by any permanent characters of 
neuration and are linked together to a great extent by intermediate forms”) may well 
be applied to Orthemis, and his example therein followed. It adds to the interest 
of these remarks to observe that Orthemis is considered by Dr. Ris to be the New 
World representative of the Old World Orthetrum. It is also worth mentioning that 
similar wide differences in the shape of the abdomen are also met with in Erythemis 
(vide posted). 
In addition to the five species named below, other South-American forms are known 
to me, one of which is described as O. flavopicta, Kirby. 
Synopsis of Mexican and Central-American Species. 
A. Hind wings with four or more rows of cells between the proximal sub- 
basal sector (A; of Comstock and Needham) and the hind margin at 
the level of the hind angle of the triangle; arculus at, or proximal 
to, the second antecubital on all wings; pterostigma 6-7 mm. long ; 
abdominal segment 2 1-1:25 times as wide as the base of segment 4, 
segment 4 1°25-1°75 times as long as wide. 
B. Labium with no median black band (its place sometimes taken by 
pale brown), femora and tibiz superiorly (exteriorly) pale brown, 
tips of wings clear or slightly smoky. Colour-pattern on sides of 
thorax consisting of five brownish stripes as follows :—one each on 
humeral suture, mesepimeron, metepisternum, second lateral suture 
(these last two broadly united at level of metastigma), and on 
metepimeron, the last diverging V-like from the preceding; mes- 
epimeral stripe often broken into two spots one above the other; 
these five stripes wider than the intervening pale areas; only one 
pale antehumeral stripe, viz., immediately anterior to the humeral 
suture. Abdomen stout, e.g. 4 mm. wide at base of segment 3; 
apex of outer hamular branch of ¢ a little produced. Abdomen, 
S$ 315-85, ¢ 31-86; hind wing, ¢ 39-48, 9 40-46mm. . . . I. ferruginea. 
* After writing the above, 1 notice that the same view is taken by Dr. Ris (Hamburger Magal. Sammelr., 
Odon. p. 43, 1904), 
