OF HARTING. 453 



which they stand, and mount aloft." Another theory 

 on this subject is enunciated by a contributor to 

 " Science Gossip" for 1868, in an article at page 124. 

 In this the motive power is attributed to " the down- 

 ward rush of numerous threads from all the spinnerets 

 at once against the current of air." " The application 

 of a similar power," he adds, " in another element, is 

 seen in the larva of the dragon fly " (see, our paper on 

 the Neuroptera) and " the flight of the skyrocket, 

 which mounts with astonishing force by the downward 

 impulse of the escaping gases." In either case the 

 threads, which are not adhesive, are gradually collected 

 together into loose masses, either by the irregular 

 action of the air, or by the aeronauts themselves, and 

 eventually fall to the ground, or become entangled in 

 the foliage of trees, or lodged against other objects 

 that arrest their flight. Thomisus cristatus (one of the 

 Crab spiders), and several species of the genera Lycosa 

 (Wolf spiders), and Theridion (Money Spinners), are 

 recorded on good authority among those that are 

 accustomed to indulge in gossamer exercise. Thomisus 

 citreus, another Crab spider, is not uncommon with us, 

 and is often found in the blossoms of the wild carrot, 

 wild parsnip, and other umbelliferous plants, patiently 

 lying in wait for the insects on which it preys. Pholcus 

 Phalangioides is very commonly found on the loose 

 webs it spins in the angles of ceilings and windows in 

 stables, out-buildings, and unfrequented rooms that are 

 not often explored by the housemaid. Its resemblance 

 to Phalangium, from which it takes its specific name, 

 is in the great length of its limbs, which, being nearly 

 transparent, give it a very frail appearance. It has a 

 curious habit of rapidly quivering its body, and, in so 

 doing, imparting a vibratory movement to its web, 

 this is supposed by some authors to be for the purpose 

 of more effectually entangling its prey. We have 

 often seen the performance on suddenly approaching 

 its web, when no prey was visible near it. 



