PSYCHE. 



REVIEW OE THE COLLEMBOLAN GENUS NEELUS AND DESCRIP- 

 TION OF N. MINUTUS N. SP. 



BV JUSTUS WATSON FOLSOM. CHAMPAIGN, ILL. 



The name Necliis murinus was given 

 by me* to a curious collembolan that 

 I found in a greenhouse in Cambridge, 

 Mass., under circumstances that in- 

 dicated Jamaica as its home. The 

 value of the generic characters which I 

 originally drew from a single species is 

 now substantiated through two more 

 forms : '■ Afegalothorax " minimus, de- 

 scribed by Willemt from specimens 

 obtained at the IjOtanic Garden of 

 Ghent, Belgium, and Ncclus minutus, a 

 Massachusetts species described below. 



The genus Neelus can now be char- 

 acterized with more detail than it could 

 before, thanks to the additional species. 

 First in importance are the extraordinary 

 development of the thorax, which greatly 

 exceeds the abdomen in length, and the 

 unusual structure of the antennae, as 

 compared with Sminthurus and Papirius 

 — the only other Collembola of globular 

 form. The head is ovate, horizontal or 

 subhorizontal, and broadly articulated. 

 Eyes and postantennal organs are absent. 

 The antennae are short — not more 



*Folsom, J. W. Neelus murinus, representing a new 

 tiiysanuran family. Psyche, vol. 7. p. 391-392, pi. 8. 1896. 



t Willem. V. Un type nouveau de sminthuride : Mega- 

 lothorax. Ann. soc. ent. Belg., t. 44. p. 7-10, i pi. 1900. 



Also, Willem, V. kecherches sur les Collemboles et les 

 Thysanoures. Brussels, 1900. (See p 65-6S and pi 15). 



than one half as long as the head — 

 and consist of four simple segments, the 

 second and third of which are incrassate 

 or subclavate. Body globular ; pro- 

 thorax slightly reduced dorsally, meso- 

 thorax not reduced, metathorax conspic- 

 uously long. Legs long and slender ; 

 coxae (fig. i) especially long; two pre- 

 coxal segments are evident. Both claws 

 present. The ventral tube is about as 

 long as the antennae and emits a pair 

 of hemispherical papillae. Abdomen 

 swollen before the manubrium ; anal 

 tubercle obsolete. Furcula twice as 

 long as the antennae; manubrium stout, 

 distally bifid ; dentes cylindrical in 

 lateral aspect ; mucrones elongate, serrate 

 or entire. Appendages sparsely clothed 

 with short stiff setae ; body almost 

 naked, except anally. Size minute. 



Tracheae are apparently absent. 

 The stomach (fig. 2) differs from that 

 of every other collembolan genus in con- 

 sisting of a longitudinal series of four 

 spherical chambers, partially separated 

 by permanent transverse invaginations 

 of the wall ; the intestine, al.so, becomes 

 spherically, but temporarily, distended 

 by its contents. The food, vegetable 

 detritus, appears through the integu- 

 ment as four or five brown ovoid masses. 



