FAMILIES L1BELLULID.E AND MYRMELEONlDiE. 185 



The libellulffi are widely extended in their distribution : they are voracious in their 

 habits, of strong muscular powers, and aide to remain long upon the wing. Their larvse 

 are quite as voracious as the perfect insect. The female deposits her eggs on the water, 

 while upon the wing. They may be regarded as serviceable to man, especially in their 

 perfect state, by feeding upon insects that are annoying, as musquitoes and the like. 



The family has been subdivided into three genera by Fabricius : 1. Lieellula proper, 

 with wings horizontal when at rest, eyes large and approximate, and having also the three 

 ocelli ; the middle division of the lip is the smallest, and the abdomen is ensiform. The 

 second genus is /Eshna, having two ocelli situated on a transverse keel-formed elevation ; 

 the intermediate lobe of the labium larger than the lateral, and armed with a strong tooth 

 and a spinous appendage ; abdomen narrow and elongated. The third genus is Agrion : 

 it carries its wings perpendicularly when at rest ; the middle lobe of the labium divided 

 in two ; the antenna? with four articulations : there is no vesicle upon the forehead ; the 

 ocelli are equal, and the abdomen filiform. 



Libellula pulchella. ( Plate xv, fig. 5.) 



Color black. Abdomen sometimes wholly black both above and below, and sometimes 

 light slate above and black below, or partly slate color : individuals seem to vary in 

 this respect without regard to sex. Wings marked by three black or dark brown spots 

 or bars : the basal is confined to the costa,and does not extend to the posterior edge ; 

 the external covers the apical area, and sweeps around so as to form a circular curving 

 edge towards the base. 

 Fig. 4 is closely allied in its habits and appearance to the pulchella, and its abdomen 

 presents in different individuals the same varieties of color. 

 Fig./. Larva of the Libellula. 



Mynneleonidae. 



( Plate sxxiii, figs. 4, 5, 6, 7.) 

 A family of insects familiarly known under the name of ant-lions, while in the larva 

 state. The insect has always arrested the attention of the curious, from its peculiar habits, 

 the singular- form of its larva, and the ingenuity it displays in making traps or pitfalls 

 to catch the prey that must serve for its sustenance. In its perfect state, it resembles a 

 Libellula ; but when it is in its larval form, we would by no means suspect that it 

 belongs to, or is the embryo of one of the most beautiful of the insect tribes. There is 

 always, however, a wide difference between insects in these two states. 



In the family of the Libellulidje, the larva is aquatic, and is provided with the ne- 

 cessary form of mouth and mandible to seize and devour other insects : it is in fact a 

 voracious animal, and carries on its depredations in the water ; while in the Mykmeleo- 

 [ Agricultural Kepokt — Vol. v.] 24 



