EPHEMERID^E. 



[ 294 ] 



EPIDERMIS. 



appearing soldered together; basal tavsal 

 joint very minute, tarsi five-jointed, termi- 

 nated in the fore legs of the male by two 

 oval pulvilli ; in the four posterior legs tarsi 

 short, five-jointed, and terminated by a large 

 oval pulvillus, and a single broad notched 

 claw. 



These insects must have been seen by 

 every one, rising and falling on the wing, 

 near the banks of rivers and pools ; in the 

 perfect state their life lasts but a few hours, 

 whence the name. The ova are deposited 

 in the water. The larva bears a considerable 

 resemblance to the pupa, from which it 

 differs in the absence of rudimentary wing- 

 covers ; they are frequently mistaken for 

 each other. 



The pupa of the common Ephemera (md- 

 gatd) (PI. 35. fig. 15) has the prothorax as 

 broad as the head, transverse-quadrate ; the 

 mesothorax gibbous ; the head rather small, 

 with two short horns in front, and two horny 

 toothed mandibles, furnished at their upper 

 angles with a long curved horn ; labrum 

 flat, membranous, ciliated, and with the 

 angles rounded ; maxillae small, membra- 

 nous, curved, pointed at the tip, and inter- 

 nally setose ; maxillary palpi four-jointed, 

 and not extending beyond the front of the 

 head ; labium large, membranous, four-lobed, 

 and furnished with a broad tongue j labial 

 palpi broad and three-jointed; antennas 

 about twice the length of the head, many- 

 jointed and ciliated ; legs short, broad, and 

 much compressed ; tarsi two-jointed, with a 

 terminal hook ; abdomen nine-jointed, the 

 six basal segments being furnished on each 

 side with a pair of elongated, rather narrow, 

 gills or branchial plates (), with long, nar- 

 row filaments at their edges, through each 

 of which a trachea extends to the tip, the 

 tracheae from each contiguous pair of fila- 

 ments uniting near the base, and then 

 running to the large tube which traverses 

 the centre of each plate ; there are in all 

 24 branchial plates. At the end of the 

 abdomen are three elegantly feathery setae. 



The pupa of Clceon another of the 

 Ephemeridae, in which the imago has two 

 wings and two abdominal setae resembles 

 that of Ephemera, but has the antennae as 

 long as the body. 



The larvae and pupae of the Ephemeridae 

 may be most easily caught in the ring-net, 

 and are admirably adapted for showing the 

 dorsal vessel, with its valves, and the circu- 

 lation. They are perhaps best preserved in 

 glycerine, or solution of chloride of calcium. 



BIBL. Westwood, Introd. ; Pictet, Ins. 

 Newopt., 1843 ; Curtis, Brit. Entom. 703 ; 

 Pritchard, Micr. lllustr. 61 (pi. 2. fig. of 

 Clceon pupa). 



EPHEM'ERUM, Ham. A genus of 

 Ephernereae(AcrocarpousMo8ses),including 

 part of Phascum of authors. 



BIBL. Wilson, Hryol. Brit. 27; Berkeley, 

 Brit. Mosses, 304. 



EPHIP'PIA. The winter-ova of the 

 Entomostraca. See EGGS and ENTOM os- 



TBACA. 



EPIBLE'MA. See the EPIDERMIS of 

 Plants. 



EPICLIN'TES, Stein. A genus of Hy- 

 potrichous Infusoria, fam. Oxytrichina. 

 (Stein, Inf. ii. ; Kent, Inf.) 



EPICO'C'CUM, Lk. A genus of Stilba- 

 cei (Hyphomycetous Fungi), parasitic upon 

 dead leaves, &c., consisting of very minute 

 gregarious tubercles, somewhat linearly 

 arranged, reddish or purplish, containing 

 numerous spherical, smooth or roujrhish, 

 reticulate spores. E. neglect um is adnate 

 to a short pedicel. When mature the 

 stroma is quite covered with spores about 

 1-2000" in diameter. Uredo Equtseti, 

 1 Br. Flora,' is an Epicoccum with smooth 

 spores. 



One species of Epicoccum, which grows 

 on decaying vegetable matter, produces a 

 form of what is commonly called Blood- 

 rain. It was developed on the calico cur- 

 tains of a shower-bath during the preva- 

 lence of cholera in 1834, and excited some 

 consternation, as it was supposed to be 

 connected with the malady. It occunvd a 

 short time afterwards in considerable abun- 

 dance on a water-melon. 



BIBL. Desmaz. Ann. Set. Nat. 2 se>. xvii. 

 95 ; Berk, and Broorne, Ann. N. H. 1850, 

 v. 406, Crypt. Bvt. 312 ; Fries, Summa Veg. 

 476. 



EPIDER'MIS OP ANIMALS. See SKIN. 



EPIDERMIS OF PLANTS. There are 

 few parts of the structure of vegetables that 

 have given rise to more discussion than the 

 epidermal cells and the tissue they consti- 

 tute. Even the term epidermis has become 

 to a certain extent equivocal, since it is 

 used by some authors in the sense in which 

 cuticle is used by others, and vice versa. Our 

 object here will be to state as briefly as 

 possible the most remarkable facts, and the 

 explanations which are received by the best 

 authorities. 



If we gently scrape the surface of the 

 leaf of a hyacinth, or other soft-leaved bul- 



