94 NEUROPTERA. 
of the mesostigmal lamine (and I can find no other), is employed because all the 
females from Central America and Southern Mexico, where A. extranea males, but no 
A. vivida males, are known, agree in having these lamine rounded and less prominent 
in comparison with the angular and more conspicuous lamine of the females from 
northern localities, where A. vivida males, but not A. extranea males, are known. It 
should be remarked here that twenty-three of the females above enum erated from Texolo 
have the mesostigmal lamine as represented in fig. 3, Tab. IV., ¢@. é. much more 
conspicuous than in other A. extranea, and with black slightly predominating over 
blue on the thoracic dorsum ; their identification as A. extranea may, perhaps, be open 
to question. 
A. extranea and A. vivida are undoubtedly near relatives and, judging from the 
males alone, exist side by side at Texolo and Cuernavaca. 
Hagen’s original description is very brief and the colours given are not applicable to 
this species. Its defects are probably due to faded specimens, as his drawings of the 
appendages agree perfectly with my identification. Moreover, in 1896, I compared 
one of these A. extranea from Teapa with types in Selys’s collection. 
31. Argia vivida. (Tab. IV. figg. 1, 2, 57, 57s, 57 ss.) 
Argia vivida, Hagen, in Selys, Bull. Acad. Belg. (2) xx. p. 406 (1865) *($ only); Calvert, Proce. 
Calif. Acad. Sci. (2) iv. p. 478, t. 15. fig. 18 (apps. g) (1895) *. 
3. Rear of the head pale. Pale (blue) antehumeral stripe from two-fifths to equally as wide as the black 
mid-dorsal stripe (see remarks below). Black humeral stripe a mere line above, wider below, where it is 
from one-fourth to equally as wide as the pale antehumeral, rarely forked. Segment 2 blue, a longitu- 
dinal black stripe each side, whose hinder end is triangularly dilated and does not reach the apex of the 
segment, or this stripe represented merely by a black anteapical spot ; 3-7 blue, each side with a black 
postbasal streak, and the apical third to fifth black; postbasal and apical black separate, except on 7 and 
occasionally on 6; on 7 the black usually occupies the whole dorsum (by widening and fusion of the 
postbasal streaks), except for a transverse basal ring ; the postbasal streaks are often absent on 3 and less 
frequently on 4 and 5; 8 and 9 blue, unmarked. 
Q. Differs from the male as follows :— Pale brown often replacing the blue of the male; segment 9 as in the 
male or, more often, with a short, black, basal stripe on either side of the dorsum. 
g 2. Pterostigma of the front wings, 1 ¢, ‘87-11 mm. ? long, surmounting more than one cell (87:5 °/, 3, 
93-6 °/, Q), one cell (11 °/, 3, 63 %/> 2), or less than one cell (1°5°/, ¢); of the hind wings 1-1-2 
long, surmounting more than one cell (95 9/, 3,90 °/, 2), one cell (2 °/, 3, 8'5°/, 2), or less than 
one cell (3°/, 3,15 °/, 2). 
Antenodal cells on the front wings 4 (83°/, 3, 90°/, 2), 5(11%, 5,3°3°/, 9), 4+ (4% 5, 2%o G), 
B+ (15 %>5 3S), B(5%o 5, 4%o 2), Or 2(66°/, 5); om the hind wings 3 (845°/, d, 91 lo 2)s 
A (12%) b47 Jo QB+ (15 %Jo FQ), Or 2 (2%o 5, 66%, @). 
Dimensions.—Abdomen, ¢ 25~32, 2 26-29°5; hind wing, g¢ 19-23°5, 9 21:5-24 mm. 
Hab. Unirep States, Lo Lo Hot Springs, Montana (MM. J. Elrod, colls. Elrod & 
P. P.C.: 8 3,4 2, 8 pairs in copula), Yellowstone (C. C. Adams, coll. P. P.C.: 16), 
Pagosa Springs, Colorado (C. F. Baker, coll. P. P.C.: 7 3), Reno (Morrison, 1878, 
M. C. Z.) and Franktown, Nevada (Denton, coll. P. P.C.: 1 6), Shasta County 
(A. W.8.: 1 ¢,1 2), San Francisco [1 ¢,1 ¢], Oakland[3 ¢, 2 2], Berkeley [1 ¢, 
