OF MANDIBULATA. 431 



and wings, all manifest their close affinity*. Yet, if the 

 Per lid es of Latreille fall into the same group with the 

 Phryganeie, such an order presents a singular discordance 

 in the external appearance of the imagines. For instance: 

 some, as Nemoura, have the corneous mandibles of the 

 Hymenoptera ; others, as Phryganea, have them scarcely 

 developed like tlie Lepidoptera ; some have a broad head 

 and the first segment of trunk large, others a small head, 

 setaceous antennae, and the first segment of trunk as small 

 as in the Hymenoptera, There are some with caudal ap- 

 pendages, others with none ; some with opaque, deflexed, 

 trichopterous wings, the upper larger than the under, others 

 witli them horizontal, membranaceous and transparent, the 

 inferior exceeding in size the superior ; some with two ocelli, 

 others with three ; and perhaps no solid character can be 

 found for Lamarck's group of Phryganidic, but the circum- 

 stance that while the perfect insects are Gymnopterous, and 

 vary excessively in external organization, the larvae are all 

 cylindrical with membranaceous feet, and undergo that me- 

 tamorphosis to which Linnteus has applied the epitl\et 

 obtecta. But, if this be the character of an order of Man- 

 dibulata, it is difficult to exclude from it the Teuthredina; 

 and indeed it is very singular that even the genus Ceplia- 

 leia of Jurine scarcely possesses a leading character, in the 

 external organization of its perfect state, which may not be 

 found either in the Perlidce or Phryganida. It conse- 



* We may hope that the learned entomologist who has revived this or- 

 der will change its name on another account, namely, that Meigen has 

 applied the word Trxchoplera to designate certain Diptera. On Phryganea 

 being indicated as a distinct order by Degeer, his commentator Retz gave 

 it the name of Elinguia. But, besides the necessity which, for the sake of 

 uniformity, there is for naming the orders from some character of the 

 wings, this, the original name of the order, is even still more objectionable 

 on other accounts, as must be sufficiently obvious. 



