2r)() H. A. HAGEN. 



Sub -family - GOMPHINA. 



I Legio GOMPHUS. 



Genus GOMPHUS. 



Selys Monogr. Goniphin. p. 12. 



This genus represents alone the Legio Gomphus. Selys. 



The known nymphae of the great genus Gomphus are homogeneous 

 in the following characters : 



1. The hind legs are more distant at the base than the fore- and mid- 

 dle legs, which are equally distant, and fitted for burrowing by a strong 

 external hook (rarely less developed or wanting) on tip of tibia, and often 

 also an internal hook on tip of femur ; the four anterior tarsi are 2-jointed, 

 the posterior ones o-jointed. 



2. The head is depressed, more or less flattened ; the antennae are 

 short, 4-jointed ; the two basal joints short, annular, the third longer 

 than both together, stout, the fourth rudimentary and very small ; the 

 eyes large, globular ; in transformation the skin splits through the middle 

 of the eyes ; the large labrum forms a kind of cap ; its front margin is 

 sharply edged by a flat plate forming inside an angle with the upper part 

 of the labrum ; in fact this plate is the front margin of the labrum bent 

 down very suddenly ; the mask reaches this flat plate and never exceeds it. 



3. The mask is flat, reaching to the forelegs, quadrangular or oblong ; 

 the middle third of its front margin is straight, or advanced in a more 

 or less produced rounded lobe, with short pavement teeth and a comb of 

 flat scales ; this lobe has sometimes one cylindrical tooth in middle, or 

 even two separated teeth ; in one instance the lobe is cleft ; the palpus 

 is small, just reaching the opposite one, rounded on tip or strongly 

 hooked, serrated or dentated on its inner margin, or plain. 



•1. The prothoracic stigma is free, uncovered ; the abdomen, twice as 

 long as broad, lancet shaped, or narrower and more elongate, spindle 

 shaped ; two longitudinal ventral sutures ending in apical angles of 9th 

 segment divide the venter in three equally broad spaces ; ventral bags on 

 the base of segments 4 to G ; segments of about equal length, but the 

 9th mostly longer than 8th, and the 10th short, even very short ; in one 

 instance longer than 9th ; appendages short, pyramidal, pointed, the in- 

 feriors a little longer than the superior, which is again longer than the 

 laterals; lateral spines present on segments 7 to 9, or 6 to 9 ; rarely on 

 5 to 9, or even on 2 to 9 ; exceptionally only on (J to 7, and once rudi- 

 mentary only on 9 ; dorsal hooks more or less developed on segments 2 



