INSECTA. 425 



Sp. Ephemera, Swammerdamia LATH., Palinyenia lonyicauda PIOTET, SWAM- 

 MEKD. 1. 1. Tab. xui. ; Ephemera vulgata L., HOUTTUYN, Natuurl. His- 

 toire, XIK Stuk. PI. 94, fig. i, PICTET, 1. 1. PI. 3, &c. 



Family XXXIII. Perlarice. Mandibles distinct, denticulate. 

 Maxillas with palps five-jointed, filiform or setaceous, and accessory 

 palp, mostly Inarticulate (galea) ; labial palps triarticulate ; lingula 

 emarginate. Antenna3 long, setaceous, multiarticulate. Wings 

 (insect at rest) cruciate, incumbent on the back horizontally; 

 inferior broader than superior, folded longitudinally like a fan. 

 Tarsi with three joints, the last with two claws, and intermediate 

 pulvillus. 



Perla GEOFFE. (Species of Phryganea L., Semblis FABK. in 

 part). Characters of family. 



These insects were first distinguished by GEOFFROY as a separate 

 genus, whilst LINNAEUS placed them amongst the P/iryganece, to 

 which they have some relation by the broad posterior wings. Till 

 within a few years it was generally supposed by writers that the 

 Perlce have a complete metamorphosis, in consequence of an imper- 

 fect observation of NOLLET, recorded by REAUMUR. PICTET however 

 has announced the metamorphosis to be incomplete ; the larvae do 

 not live in cases, but mostly in running water, by preference under 

 stones. Some have at the thorax external respiratory organs ; others 

 breathe through closed stigmata, which have the same situation as 

 the future apertures of the perfect insect, and take in the air by 

 endosmose. They have constantly two threads at the hinder part of 

 the body, which sometimes disappear in the perfect insect, but in 

 many species persist at that period. The males of some species have 

 short wings, merely rudimentary. 



Comp. on this family, of which more than a hundred species from all 

 parts of the world are now known (through later investigations and dis- 

 coveries), PICTET, Mem. sur les larves de Nemoures, Ann. des Sc. not. xxvi. 

 1832, pp. 369 391. PI. 14, 15; ejusd. Mem. sur les metamorphoses des 

 Perles, Ann. des Sc. not. xxvm. 1833, pp. 44 65, PL v. vr. and his Hist, 

 nat. des Insectes Nevropteres, Premiere Monographic, Famille des Perlides. 

 Geneve, 1841. 8vo. 



Sub-genera: Perla LATR., mihi (Kollaria PICTET, Eusthenia 

 WESTWOOD, Pteronarcys NEWM., Perla PICTET), Capnia PICTET. 



Anematura mihi (Nematoura LATR., PICTET). 



Note. This family with the following approaches by natural affi- 

 nity very nearly to the Orthoptera. 



