OCR Text |
Show 1877.] COLLECTION M A D E B Y 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 convinced represent the nearly mature condition of two ; and it may be that they pertain to the Pantala and Tramea respectively. The larger form (Pantalal) (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 marginal 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 inferior 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 tibias there are indications of broad fuscescent rings, and the intermediate and posterior tarsi are blackish. |