THE COLLEMBOLA. 



149 



pound eyes. Campodea stapJtijlinus, a small elongated species about a sixth of an inch long, with two 

 caudal bristles, is common in loose, damp ground both in England and on the continent. It has the 

 palpi short, and all the parts of the mouth minute, and is regarded by Sir John Lubbock as a sort of 

 central type, from which many others have been derived. It is the type of the family CAMPODEID.E. 

 Both this and the family JAPYGID.E show a strong affinity to the second tribe (the Collembola). 

 Japyx solifitt/xs. a white species less than half an inch long, is found under stones in different parts 

 of the south of Europe. It is much elongated, and the abdomen terminates in a pair of little horny 

 forceps, closely resembling those of the Earwigs. Another species (Japyx giyfis), from Cyprus, is the 

 giant of the Thysanura, sometimes measuring more than an inch long. 



TRIBE II COLLEMBOLA, OR SPRING-TAILS. 



The Collembola. which correspond to the family Podurida? of most authors, have the antennte 

 comparatively short, and composed only of from four to six joints ; the organs of the mouth concealed 

 within the buccal cavity, and destitute of palpi, except a pair of rudimentary organs, which Sir John 

 Lubbock identifies with the maxillary palpi in certain species ; the prothorax small ; the tarsi of a 

 single joint, and the abdominal appendages represented by a single 

 pair springing from a segment near the apex (the last but one, or the 

 last but two), united at the base to form a springing fork, and bent 

 forward in repose, so as to reach nearly or quite to the head. By the 

 action of this fork, the arms of which are frequently jointed, and 

 furnished with adhesive hail's, the insects thus endowed are enabled to 

 spring to a considerable height in the air, the process being precisely 

 analogous to that by which the common toy frogs are made to jump. 

 In form these insects are sometimes irregularly globose, but more 

 commonly rather elongated, although never presenting the rather 

 elegant, fish-like shape of many of the preceding tribe. Their surface 

 is covered with hairs or scales, or with a mixture of both. The tarsi 

 are terminated by a single curiously-cleft claw. The abdomen con- 

 sists of six segments, on the ventral surface of the first of which there 

 is a very peculiar organ. This consists of a cleft tubercle, or a short 

 tube divided at the free end into two lobes, from which the animal 

 can protrude two long, delicate tubes, covered with minute glands, 

 by means of which, and of a viscous fluid produced by these curious 

 organs, their fortunate possessors are enabled to adhere with facility 

 to smooth vertical objects upon which they may be walking. Accord- 

 ing to some writers, there ai-e four pairs of stigmata upon the first 

 foiir segments, leading into a regular tracheal system ; but the exist- 

 ence of the latter is by no means demonstrated in all the forms of this 

 tribe. Sir John Lubbock seems to have detected trachea? only in one 

 genus examined by him (Smi/nthnrus), and he declares that the 



stigmata leading into these trachese are situated upon the under side of the head. This is a most 

 unusual situation for the tracheal openings. 



The Collembola are all small insects, a length of a quarter of an inch being considerably above 

 the avei-age. They are found commonly in loose earth, under decaying leaves in woods, in moss, 

 under the bark of dead trees, and in rotten stumps. They always prefer damp situations. Cold 

 seems to have but little effect upon them ; they will recover their activity after being frozen. 

 One species (Desoria gfiirioUn) is found enjoying itself upon the Swiss glaciers ; and another 

 (Degeeria nircdis) occurs upon the surface of snow in many parts of Europe. Some also may 

 be met with hopping about upon the surface of standing water ; Podnra aquatica, a minute blue- 

 black species, is common in such situations in England. Orchesella cincta, one of the finest and 

 handsomest species, a quarter of an inch long, distinguished by having a black band on the third 

 segment of the abdomen, is found commonly under dead leaves, and in moss; Toxocerus phimbeus, 

 a rather smaller species, is found under logs of wood. W. S. DALLAS. 



OKCHESELLA CIXCTA. 



