54 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. XXVIII. 



life — the stag-e of growth and development. After one or two molts 

 in tills stage some forms approximate closely in appearance to the adult 

 condition. Hence there are names for the various portions of the 

 nymphal mite, the earlier part being the protonymph, then the deuto- 

 nymph, and sometimes a tritonymph. These terms 

 are applied in the true Gamasida?. In the nymphal 

 stage some Gamasids are attached to various insects 

 for the purpose of transportation. In fact, some 

 genera (as Uropoda) nvc chiefly known to us in this 

 migratorial nymphal condition. Various writers 

 ^— -— -^ vi/j^y have claimed that the mite was a parasite of the 

 \j~\,.^ /%^ insect, but such is not the case. The insect is used 

 only as a means of transportation. In some cases 

 tlie mite is attached to the insect by an anal pedi- 

 cel formed of excretions. Such a one is known as 

 a " nynipha peduncidata. "" In some cases the nymph 

 may pair and produce eggs; these are called " nympha pedogenica." 

 The nymph from the larva is often more like the larva in many ways 

 than like the adult. This tirst nymphal stage is called ''nympha hete- 

 romorpha." The nymph after molting may look like the adult; this 

 second nymph is the ''nympha homeo- 

 morpha." These latter two terms are 

 applied only in the Uropodidfe. Some 

 Gamasids live in decaving- substances, 



Fig. iHi.— I'NEUMoNYssrs: 



BEAK, CL.WVS, .\ND STIG- 

 MA L I'LATE. 



Fui. 97.— HaLARACHNE AMERICANA. .V, STERNUM 

 OE MALE; t, STIGMATA AND COXjE: .r, MANDIBLE. 



Flu. 98. — H-EMOGAMA.SUS AMERICANOS, 

 AND ANAL PLATE. 



either animal or vegetal)le. It has been show^n that certain Uropodidfe 

 live on minute plants, bacteria, and small fungi. Most species prey 

 on small insects, Thysanurans, other mites, as Tyroglyphidte and Erio- 

 phyidas and occasionally they will eat one another. 



