84 



HARDWICKE'S SCIENCE-GOSSIP. 



with the tubes comprising the respiratory system on 

 each side, ramifying into the gills. 



The Skeleton, or Phaiitojn larva (that of a fly, 

 Corcthra pluviicoriiis) is also found in winter, not- 

 withstanding its fragile nature. The popular names 

 given to this strange creature well agree with its 

 weird and ghostly aspect : nothing can be imagined 



The water of almost every pond, ditch, and stream 

 contains countless little creatures — some hardly visi- 

 ble to the naked eye — swimming about with great 

 rapidity, known as Entomostraca. All workers with 

 the microscope, and all such as search after the 

 secrets of pond-life, are familiar with the commoner 

 species. The common Cyclops {Cyclops qiiadricorius) 



Fig. 58. — Larva of Ephemera, a, a, a, Spiracles ; 

 b, b, b, lateral tracheae ; the chain of nervous gan- 

 glia is seen running up the middle. 



more like an aquatic pliantom than the shadow-like 

 form of its almost fluid body, while it is the very 

 picture of the skeleton of a larva. Despite its ap- 

 parent delicacy, it is armed with a formidable mouth- 

 apparatus, for its food consists chiefly of the lively 

 little Entomostraca, which it seizes by imperceptibly 

 twisting its little body up to the intended victim and 

 then making a dart.* Another notable larva is that 

 of the dragon-fly ; an enormously cruel life-destroyer, 

 almost as voracious as that of D. viarginalis and far 

 more cunning. Passing over this larva, together with 

 those of many flies, gnats and water beetles, we come 

 to a class of animals differing much from the pre- 

 ceding, and well suited for microscopic study. 



* A very full account of this curious larva, with accurate 

 figures, will be found in Science-Gossh' for t858. 



Fig. 59 — Cyclops vulgaris {female, and young)- 



Fig. 60. — Daphnia pitlex (male, 

 magnified). ^___. 



is perhaps the most abundant species of this nume- 

 rous tribe. All the year round it occurs in nearly 

 every stagnant pond, as well as in the clearest spring- 

 wells ; even in winter its multitudes swarm in water 

 containing duckweed (Lemna). The female is much 

 more plentiful than the male, from which she is dis- 

 tinguished by the long antennce, which are smooth 



