APHANOCAPSA. 



[ 52 ] 



APHIDiE. 



and Nostochinese, as indicated by Hassall. 

 Its filaments agree with Oscillatoria, but are 

 distinguished by the conspicuous spermatic 

 cells, resembling those of Dolichospermum, 

 and it diifers from all the rest of the Nosto- 

 chineee in the absence of vesicular cells and 

 the obscurity of the articulations of the 

 filaments. Ralfs enumerates three British 

 species, viz. — 



1 . A. Flos-aquce, Linn. — Filaments cohe- 

 ring laterally in flat lamellae which separate 

 at their extremities into fasciculi ; spermatic 

 cells cylindrical, with an inconspicuous 

 covering. — Ralfs, Ann. Nat. Hist. ser. ii. 

 V. pi. 9. fig. 6. Sjn. Oscillatoria Flos- 

 aquce, Agardh, Sysi. Alg.; Nostoc Flos- 

 aqucB, Jiirgens; Limnanthe Linncei, Kiitzing, 

 Linncea, xvii. 86 ; Limnochlide Flos-aquce, 

 Kiitz., Fhycologia Generalis, Fhycologia 

 Germanica, and Tabulce Phycologicce, cent. i. 

 pi. 91. fig. 2 a. (PI. 4. fig. 1). 



2. A. cyaneum, Ralfs. Filaments free, ag- 

 gregated into a thin mucous stratum; sporan- 

 gia linear, 8 to 1 2 times longer than broad, with 

 a conspicuous hyaline covering. — Ralfs, I. c. 

 pi. 9. fig. 7. himnoclilide Flos-aquce var. 

 hercynica, Kiitz., Species Alg.-, Tabulce Phy- 

 cologicce, cent. i. pi. 91. fig. 11 ? 



3. A. incurvum, Morren. " Filaments 

 articulated, cohering together in flat laminae, 

 laciniated at the apex ; articulations 2 to 8 

 times longer than broad." Mr. Ralfs states 

 that the Irish specimens identified by Morren 

 do not agree with this character, being held 

 together by the mucous matrix rather than 

 coliering, as in Flos-aquce, and they are 

 neither fasciculated nor laciniated at the 

 ends. — Ralfs, I. c. pi. 9. fig. 8. Ajjh. incur- 

 vum, Thompson, Ann. Nat. Hist. v. 82 ; 

 Harvey, Manual of Brit. Algce (ed. 1), 145 ; 

 Hassall, Brit. Freshwater Algce, t. 76. 

 fig. 6. Limnochlide Flos-aquce var. Har- 

 veyana, Kiitz., Tabulce Phycologicce, cent. i. 

 pi. 91. fig. 2. 



BiBL. For further details consult Mr. 

 Ralfs's paper on the Nostochinece, Annals of 

 Natural History, 2nd ser. v. 339, 1 850, and 

 the other works cited above. 



APHANOCAPSA, Nageh.— A supposed 

 genus of Unicellular Algae. See Pal- 



MELLA. 



APHANOCHiETE, Braun.— A genus of 

 Chffitophoreae (Confervoid Algae) allied to 

 Coleochcete ; the bristles arising from the 

 backs of the cells are not sheathed, but arti- 

 culated in the upper part.' Not yet detected 

 in Britain. 



BiBL, Alex. Braun, Verjungung, p. 196, 



&c. &c.; Ray Soc. Translation, Rejuvenescence 

 in Nature, 1853, p. 184, &c. 



APHANOTHECE, Nageli.— A supposed 

 genus of Unicellular Algae. See Palmella. 



APHIDiE. — Afamily of Insects belonging 

 to the order Hemiptera (Homoptera, West- 

 wood). This family comprises the insects 

 forming the lice of plants. 



Rostrum more or less perpendicular or 

 inflexed, varying in length, being in some 

 species nearly half as longasthebody, and con- 

 sisting of four joints. Labrum long and pointed 

 at the tip ; antennae of moderate or of great 

 length, setaceous or filiform and 7-jointed, 

 the last joint being sometimes obsolete 

 and the third longest. The ocelli, three in 

 number, form a large triangle ; the eyes are 

 entire, prominent, and semi-globose. The 

 thorax is oval, with the protothorax forming 

 a transverse collar; the abdomen is short 

 and convex, ovate or elongate-ovate, soft, 

 and generally furnished with a more or less 

 elongated tubercle on each side near the ex- 

 tremity. The wings are very much deflexed 

 at the sides of the body, being almost per- 

 pendicular in repose ; the fore wings much 

 larger than the posterior, with strong nerves, 

 the subcostal nerve terminating in an elon- 

 gated stigma, close to which runs another 

 longitudinal nerve, obliquely emitting two or 

 three straight nerves, which run to the hind 

 margin of the wing, the last of which emits 

 one or two branches ; the posterior wings 

 have two similar oblique nerves. The legs 

 are long, or very long and slender, formed 

 only for crawling ; the tarsi short and two- 

 jointed, the basal joint being shortest. 



The pupa state is active, and resembles 

 the imago, except in possessing rudiments of 

 wings upon the back; but some never acquire 

 wings, in which case the pupa cannot be distin- 

 guished from the mature larva or imago states. 



The species are found upon almost all 

 kinds of plants, the juices of the young parts 

 of which they suck by the assistance of their 

 proboscis, producing frequently disease in 

 the plant, either by greatly weakening it, or 

 by distorting young shoots and leaves ; some 

 species raising vesicles, or other gall-like ex- 

 crescences, in which whole generations of 

 aphides are residents. 



The above-mentioned anal tubercles se- 

 crete a saccharine fluid, of which ants ai*e 

 very fond ; and it is this fluid dropped upon 

 the adjacent leaves, or the extravasated sap 

 flowing fi'om the wounds caused by the 

 punctures of the insects, which is known 

 under the name of honey-dew. 



