398 SUPPLEMENT. 
PROGOMPHUS (p. 148). 
Progomphus obscurus borealis (p. 151). 
Page 151, line 18, for ‘“ thoracic carina ” read “ thoracic suture.” 
To the localities given, add :—MeExico, Bafios de Santa Rosalia (Calvert, coll. 
P. P. €.: 3 3) in Chihuahua. 
This species and Erpetogomphus crotalinus were found on sand- or mud-banks, 
hardly above water-level, along the sides of an irrigating ditch into which the water 
from the baths of Santa Rosalia empties. On alighting on these banks, P. obscurus 
borealis held its abdomen slanting upward to form an angle of 45°-60° with the bank, 
while Z. crotalinus held it nearly horizontal. 
GOMPHOIDES (p. 152). 
Gomphoides volsella (p. 156). (Tab. X. fig. 48.) 
The new figure is to replace that of ‘Tab. VII. fig. 14. 
Gomphoides ambigua (p. 157). 
The two males from San Felipe, Guatemala, listed anted, page 157, were received as the final proof was 
passing through my hands, when it was not convenient to add certain notes on them which here follow. 
They have the dilated margin of abdominal segment 9 much narrower (‘25 mm.), the pale stripes on the 
thorax wider (¢. g., maximum width of first antehumeral stripe ‘8--9 mm., of mesepimeral stripe 1:2 mm.), 
and the pterostigma shorter (its costal edge on front wings 4°5 mm.) than in the Mexican examples, the 
corresponding dimensions in most of which are 1, -3--5, ‘5-9, and 5 mm. However, isolated instances 
occur among the Mexican material which approach the conditions found in these two Guatemalan males. 
Thus a teneral male from Guadalajara has the pterostigma 4:5 mm., although the dilated margin of 
segment 9 is 1 mm. wide. Another Guadalajara male has this dilated margin -6 mm. wide, although in 
other respects agreeing with the Mexican specimens. The male from Altamira has the first pale ante- 
humeral stripe as wide as in those from San Felipe, but is otherwise like its compatriots. 
ERPETOGOMPHUS (p. 159). 
The most southern locality for this genus certainly known is now San José in 
Costa Rica, as cited below under £. elaps. 
Erpetogomphus elaps (p. 163). (Tab. X. figg. 30-34.) 
To the localities given, add:—Costa Rica, San José (Biolley: 1 3). 
This additional male has directed my attention to the considerable variation in the 
first hamule of males of this species from various localities, illustrated in our figures. 
I do not find any other feature varying correlatively. 
Erpetogomphus cophias (p. 164). (Tab. X. fig. 47.) 
The new figure is to replace that of Tab. VII, fig. 33. 
