116 

 kinds that prey on the lesser genera, have prevented such an increase of them as to become 

 in a Uttle time a plague too great to be borne ? No. The Almighty Creator has most 

 wisely constituted this genus for executing His commands in the manner I have described ; 

 and for this reason they must be considered as beings of greater consequence than the 

 inconsiderate part of mankind allow them to be. 



" Nor is this the only advantage arising from their existence. The still waters, where 

 these creatures are inhabitants during their infant state, are in some degree by their 

 assistance preserved sweet and good, that otherwise might corrupt and putrify-, for the 

 motion the waters receive by these insects is not trifling ; the respiration they perform in 

 that element being observable by a close attention, which, together with that and the motion 

 of thousands of other insects, does in some measure contribute to keep it sweet and 

 wholesome." 



LIBELLULA LYDIA. 



Plate XLVII. fig. 4. 



Okder ; Neuroptera. Section : Subulicornes. Family : Libellulida-, Leach. 



Gends. Libellula, Linn. Sj-c. 



LiBELLULA Lydia. Siibaenea, abdomine {$) coeruleo lateribus luteis, alis hyalinis, singula striga parv^ basali 

 fasciaque lata transversa pone medium, fiiseo-chalybeis. (Expans. Alar. 2 unc. 9 lin.) 



Syn Libellula Lyciia, X))-Hr(/, ^/)p. t'o/. 2. 



Habitat: Virginia. 



Front of the head green. Eyes dark brown, very large, and placed near each other. Thorax 

 green, having on each side two transverse yellow stripes. Abdomen of the male blue, with small yellow 

 indented marks on the sides ; that of the female yellow ; the former having two little horny substances 

 like tails at the extremity, which are wanting in the female. Wings reticulated and transparent ; the 

 middle of each being of a very dark blue colour, occupying about a third part, and crossing them from 

 the anterior to the posterior edges, which by the reflection of white paper becomes dark brown. A dark 

 brown stripe also, about a quarter of an inch in length, issues from the base of each wing, almost joining 

 to the anterior edge ; below which the males have a white patch placed on their interior wings. 



^:SHNA JUNIA. 



Plate XLVII. fig. 5. 



Order: Neuroptera. Section; Subulicornes. Family: Lihellulidee, Leach. 



Genus. .Sshna, Fabr. Libellula, Linn. %-c. 



jEshna Junia. Fuscescens, unicolor (in vivisvirescens ?), alis hyalinis, costa pallide infuscata, stigraate oblongo, 



nigro. (Expans. Alar. 4 unc. 3 lin.) 

 Syn. Libellula Junia, iJcHr^, App.vol.i. 

 Habitat: New York. 



Head large, and in front of a brown yellow. Eyes brown, almost black, large, and placed close 

 together. Thorax, when the insect was living, apparently green. The abdomen is now brown, but 



