130 



SCIENCE-GOSSIP. 



all yEschnae diverge. The leg-processes are short ; 

 they enclose a right-angle. The hinder process is 

 much the larger and is laterally rounded. This 

 larva, by far the most common, occurs almost 

 everywhere in ponds and marshes. 



JE. grandis is reddish. The leg-processes are 

 sharp and bent slightly outwards, the anterior 

 somewhat slender. The prothoracic spiracles are 

 very visible. This, the next common species to 

 cyanea, is found in the same situations. 



JE. isosceles has the hinder angles of the head 

 rounded as in cohiberculus . The leg- processes are 

 triangular, sharp, and enclose an acute angle, the 

 anterior being half the length of the posterior. The 

 lateral caudse are longer than in the other species, 

 being but one-fourth shorter than the middle piece. 

 This species is rare, confined to marshes in the South. 



We now arrive at the second great division of 

 the dragon-flies, the Agrionidae, of which the 

 insects placed in Leach's genus Calopteryx form 



antennae stout, very long ; the spineless body 

 filamentous and terminated by three caudse only, 

 grooved lengthwise ; the mask is long and flat, 

 with a central diamond-shaped opening ; the 

 thoracic spiracles are hidden ; the tibia? have a 

 short tooth apically. The nymphae inhabit reedy 

 streams, sitting on bottom-growing plants and 

 moving but rarely. 



AGRION virgo. The head of the nymph, as 

 shown in the accompanying figure, will enable the 

 species to be at once recognized. Reaumur's 

 figure and description refer, I think, to the next 

 species. The present one is generally distributed 

 in England, but scarce in Ireland. 



A. splendens is very like the last ; the projections 

 on the head are wanting ; the central caudal plate 

 is shorter than the others ; the eyes less prominent, 

 and the head is bluntly pointed. Three small 

 tubercles, disposed triangularly, occur occipitally. 

 There are two semi-circular spots basally on each 



o Larvae of Dragon-Flies. 



Fig. 7 is that of Gomphns vulgatissimus ; a, its " mask," and b, its abdominal extremity. Fig. 8 is Cordulegaster annnlatus ; 



a, its abdominal extremity. Fig. 9 represents Anax imperator ; a, the tip of its " mask," and b, the leg-base processes. 



The next two figs, show the relative contours of (i2d) JEschna juncea and (13(f) JE. cyanea. 



the types. Leach's name has been sunk in favour 

 of Linne's original type-name, Agrion. The peculiar 

 biform respiratory system of the larvae of this 

 group has already been mentioned. The generic 



segment above. The caudae are ribbed medially ; 

 the middle one is half the length of the others and 

 slightly rounded apically. This species is generally 

 distributed throughout Great Britain, and occurs 



characters of Agrion larvae are : basal joints of in similar situations to A . virgo ; but the two 



