NO. 2192. DRA00NFLIE8, CALIFORNIA AND NEVADA— KENNEDY. 527 



could save an insect of this size from being buried in the movmg 

 sand. 



The nymph of Progomphus has been described by Dr. J. G. Need- 

 ham as follows : ^ 



Head depressed, sloping anteriorly, cordate, broadly notched behind; hind angles 

 rounded. Antennae inserted into cylindroid elevations on the front, depressed and 

 incurved so as to almost surround the pilot-shaped labrum: two basal joints very short; 

 third, twice as long as the two basal combined, slightly flattened and upcurved at the 

 tip; fourth joint small, one-third to one-fifth \phscuriis] as long as the third, slender 

 and strongly recurved. 



Labium rather small, reaching, when folded, to the bases of the middle legs; sub- 

 mentum shortened; mentum narrowed at its proximal end, its median lobe promi- 

 nent, rounded, fringed with a row of flabellate scales whose bases are overlaid by 

 another row of shorter semicylindrical scales; beneath this fringe, the margin cut into 

 a series of obscure rectangular teeth; lateral lobes short, nearly straight, unarmed, 

 rounded at apex; movable hook stout, moderately incurved, and tapering. 



Thorax sloping to the head and to the bases of the legs; prothorax of unusual 

 dimensions on the dorsal side, its hind margin on line with the bases of the hind legs, 

 being extended back upon the other thoracic segments, shield shaped, with a short 

 collar close behind the head. Wing-cases strongly divergent. Legs conspicuously 

 fossorial, fore legs approximate to the sides of the head, bearing shields of stiff hairs 

 behind which the middle legs may be brought forward. Middle legs approximated 

 on the venter, rotated downward and extended horizontally close under the fore 

 legs. Hind legs longer, more nearly normal, directed posteriorly. Fore tarsi with 

 soles facing laterally; middle tarsi rotated on tibise so as to point backward; hind 

 tarsi elongate, the third segment about as long as both basal segments, its claws sharp 

 and long; claws of fore and middle tarsi short and blunt. Each femur with a distal 

 anterior process which rests against and supports the tibia when moved backward. 



Abdomen spindle-shaped [oftscwras], segments about equal, the ninth a little longer 

 than the others; dorsal hooks variable, rudimentary, more or less well represented on 

 segments 2 to 9 \_ohscurus\. Lateral spines on 5 to 9 [ohscurus], on 5 rather minute. 

 Appendages slender, tapering, superior and inferiors equal, about one third longer 

 than segment 10, laterals about half as long as the others. 



The preceding description was written for the eastern species, 

 Progomphus ohscurus (Rambur). I beheve the Pacific coast form to 

 be a distinct species, so it would have to be called Progomphus horealis 

 McLachlan. It diffei-s in the imago in being larger than ohscurus 

 and in having a single row of denticles on the inferior side of the male 

 superior appendages (fig. 154). In ohscurus, as pointed out by Cal- 

 vert,2 the posterior end of this row is double or treble. 



I have quoted the description of ohscurus from Needham and have 

 figured the horealis nymph to show that the differences between the 

 two species are more conspicuous in the nymph than in the adult. (See 

 figs. 155-163.) 



The specific characters of the horealis nymph may be given as 

 follows : 



Length shorter than that of ohscurus nymph and v/idth greater so that 

 the horealis nymph has none of the appearance of extreme slenderness as 



1 Needham and Hart., Bull. 111. State Lab. Nat. Hist., vol. 6, art. 1, 1901, pp. 55-56. 

 « Biol. Cent. Amer., Neur., p. 149. 



