1877. ] COLLECTION MADE BY H.M.S. ‘ PETEREL.’ 85 
only a very small dark anal spot on the hinder wings, in this latter 
character differing from most of the species of Central America. 

There are also two “ nymph’’-forms, which I was at first inclined 
to consider only conditions of one species, but which 1 am now con- 
vinced represent the nearly mature condition of two; and it may be 
that they pertain to the Pantala and Tramea respectively. 
The larger form (Pantala®) (fig. 1) may be described as follows :— 
Length, 23 millims. Body above (exceptiug the eyes and anal 
processes) uniformly opaque, pulverulent, brownish grey ; beneath, 
dingy yellowish and shining. Eyes yellowish. Mask of labium 
elongate, its anterior edge forming a triangle with obtuse apex. 
_Mandibles very large and prominent, standing out much in advance 
of the front of the head, their interlocked edges with about eight 
rather blunt teeth; very convex externally, forming (with the mask) 
a gibbous projection. Head above with a large and deep triangular 
depression behind the region of the ocelli. Pronotum with rounded 
hinder margin. Anterior rudimentary wings very narrow, lanceolate, 
extending to the hinder suture of the sixth abdominal segment ; 
posterior broad in the anal portion, rather longer than the anterior. 
Abdomen short and broad, a small black triangular spot in the 
middle of the hinder suture of each ventral segment; the alate mar- 
ginal portion very broad if viewed from beneath. Eighth segment 
produced at the sides into a strong flattened acute tooth, furnished 
with small distant spines on the edge. Ninth produced into a much 
longer and broader curved tooth, broadly triangular at its base, also 
with small spines on its edge. The form of the anal valves &c., is 
as follows :—Median dorsal process long and very strong, its sides 
dilated and triangular at base, the upper edge forming a sharp keel. 
Lateral superior processes slender and much shorter. Lateral infe- 
rior processes long, lanceolate, and very acute, scarcely shorter than 
the median dorsal process, slightly curved. All the anal processes 
shining, and dingy yellowish. Legs slender, not especially long, 
concolorous with the body; but on the femora and tibie there are 
indications of broad fuscescent rings, and the intermediate and pos- 
terior tarsi are blackish. 
