55 



Another common form is Diplax herenice, (Fig. 45, male ; Fig. 46, female). The ac- 

 companying cut (Fig. 47.) represent.s the larva, probably of this species, accord- 

 ing to Mr. Uhler. It is black, the head blue in front, .spotted with yellow, while 

 the thorax and abdomen are striped with yellow. There are fewer stripes on 

 the body of the male, which has only four large yellow spots on each side of the 

 abdomen. 



Still another specimen is Diplax Elisa. It is black, with the head yellowish 

 and with greenish yellow spots on the sides of the thorax and base of the 

 Fife'- 47. abdomen. There are three dusky spots on the front edge of each wing, and a 

 large cloud at the base of the hind pair towards the hind angles of the wing. 



Rather a rare form, and of much smaller stature is the Nan- 

 nophija bellii, (Fig. 48.) It was first detected in lialtimore, and was 

 afterwards found uufrequently by a pond in Maine. Its abdomen 

 is unusually short, and the reticulations of the wings are large and 

 simple. The female is black, while the male is frosted over witl 

 a whitish powder. 



In the allied genus Agrionina, there are many interesting insects ; 

 we give an illustration in fig. 40. of one of the mo.-it common, Agrinn 

 smtcium. This insect is smaller in size than those we have previously 

 mentioned. 



AlthdUgh in this country we rarely see Dragon-flies gathered in 

 large numbers at one time, yet it is known that in some countries they 

 not unfrequontly form uiimense swarms. In Kirby and Spence's En 

 tomology we find the following : — " Meineckcn tells u.s, that he once 

 saw in a Village in .\nhalt, on a clear day, about fuur in the afternoon, 

 such a cloud of Dm^oB-iies (Lihelluliiui) as almost concealed the sun, 

 and not a little alarmed were the villagers, under the idea they were 

 locusts ; several instances are given by Kosel, of similar clouds of these insects having been 

 seen in Silesia and other districts ; and Mr. Wooluough, of Ilollesley in Suffolk, a most at- 

 tentive observer of nature, once witne.s.scd such an army of the smaller dragon-flies, ( Aijrion) 

 flying inland from the sea, as to cast a slight shadow over a field of four acres, as they passed. 

 A migration of Dragon-flies was witnessed at Weimar, in (iorniany, in 1810, and one 

 far more considerable, perhaps the greatest on record. May 30th and 31st, 1831), when cloud- 

 like swarms of these insects, chiefly (LdicUula dcpressa) were seen at Weimar, Eisenach, 

 Leipsig, Halle and Gottingen, and the intervening country, extending over a largo district." 

 Although so well known in the adult or perfect state, comparatively little is known 

 of the transformations of Dragon-flies. They may be easily kept in aquaria where their 

 various changes may be watched, and any one who can spend the necessary time and 

 patience in rearing them, so as to trace up the differiuit stages from the larva to the adult 

 fly, and describe and figure them accurately, will do good service to science (Packard). 



The graceful appearance of these insects has not escaped the notice of poets, Yor 

 Moore alludes to them as " the beautiful blue damsel flies," while Tennyson, in his poem 

 of the " Two Voices," gives the following description : — 



To-day I saw the Dragon-fly 



Come from the wells where he did lie. 



An inner impulse rent the veil 



Of his old liusk : from lioad to tail 



Came out clear plates of sapphire mail. 



He dried his wings : like gauze they grew ; 

 Through crofts and pastures wet with dow 

 A livin}; flash of lijjlit ho flow. 



Fig. 49. 



